Archives for posts with tag: natural selection

Your Ancestors, Your Fate“The notion of genetic transmission of ‘social competence’ — some mysterious mix of drive and ability — may unsettle us. But studies of adoption, in some ways the most dramatic of social interventions, support this view. A number of studies of adopted children in the United States and Nordic countries show convincingly that their life chances are more strongly predicted from their biological parents than their adoptive families. In America, for example, the I.Q. of adopted children correlates with their adoptive parents’ when they are young, but the correlation is close to zero by adulthood. There is a low correlation between the incomes and educational attainment of adopted children and those of their adoptive parents. These studies, along with studies of correlations across various types of siblings (identical twins, fraternal twins, half siblings) suggest that genetics is the main carrier of social status.” – from gregory clark. see also The Son Also Rises: Surnames and the History of Social Mobility.

Reductionism! Determinism! Straw-man-ism!” The main problem, it seems to me, is a fundamental misunderstanding of what genetics as a science studies and how it relates to the function of complex systems. The following statements are not contradictory: 1. The function of a complex system emerges from the complex and dynamic interactions between all of the components of the system, in a context- and experience-dependent manner. 2. Variation in single components of the system (or in multiple components) can affect how it functions. Geneticists investigate the second question. Showing that variation in Gene X affects the behaviour or outcome of a system is not the same as saying that Gene X fully determines that behaviour or fully accounts for the entire system. Gene X is just a piece of DNA sitting in a cell somewhere – it doesn’t do anything by itself. But a *difference* in Gene X can account for a *difference* in how the system works. – from kevin mitchell.

The Problem with HBD, the Dark Enlightenment, Neoreaction, Alt-Rightism, and All That Jazz – READ THIS! – from jayman (and misdreavus).

There’s nothing wrong with looking for ‘gay genes’“The Left loves to tell the Right that it’s anti-science, pointing (not without reason) to the correlation between conservative beliefs and a failure to come to terms with the scientific facts of evolution and human-caused climate change. But there’s a subtler tendency on the Left; a fear of research into human nature, in case the findings are in some way politically uncomfortable.”

Evolution equally efficient in removing deleterious variants in Europeans and West Africans“…but apparently not in Denisovans who accumulated deleterious mutations at a higher rate than modern humans.” – @dienekes’.

Scientists unlock a ‘microbial Pompeii’“An international team of researchers have discovered a ‘microbial Pompeii’ preserved on the teeth of skeletons around 1,000 years old. The key to the discovery is the dental calculus (plaque) which preserves bacteria and microscopic particles of food on the surfaces of teeth, effectively creating a mineral tomb for microbiomes.”

The effect of paternal age on offspring intelligence and personality when controlling for paternal trait level [pdf] – “We examined the effect of father’s age at birth on offspring intelligence, head circumference and personality traits. Using the Minnesota Twin Family Study sample we tested paternal age effects while controlling for parents’ trait levels measured with the same precision as offspring’s. From evolutionary genetic considerations we predicted a negative effect of paternal age on offspring intelligence, but not on other traits. Controlling for parental intelligence (IQ) had the effect of turning an initially positive association non-significantly negative. We found paternal age effects on offspring IQ and Multidimensional Personality Questionnaire Absorption, but they were not robustly significant, nor replicable with additional covariates. No other noteworthy effects were found.” – from lars penke.

Reversed hierarchy in the brain for general and specific cognitive abilities: A morphometric analysis“Here, we analyze gray matter with three morphometric indices (volume, cortical surface area, and cortical thickness) at three levels of the intelligence hierarchy (tests, first-order factors, and a higher-order general factor, g)…. The key finding reveals substantial variability in gray matter correlates at the test level, which is substantially reduced for the first-order and the higher-order factors. This supports a reversed hierarchy in the brain with respect to cognitive abilities at different psychometric levels: the greater the generality, the smaller the number of relevant gray matter clusters accounting for individual differences in intelligent performance.” – h/t ben southwood!

A nice bunch of flowers“The general factor of intelligence is strongest at lower levels of intelligence. It may be a case of ‘All neurones to the pump’. When abilities are low, most problems are difficult. In such cases, all resources have to be thrown at the problem. When abilities are higher there is more spare capacity for differentiation of abilities. Brighter persons have a lower proportion of their abilities accounted for by a common factor, even though the have higher absolute abilities.” – from dr. james thompson.

GED scores by Ethnicity and Nation – from chuck @human varieties.

The Unfortunately Innate Nature of Intelligence“You cannot blame people for being what they were born, and you cannot expect them to do what they cannot.”

Psychologist on a mission to give every child a learning chip“Prof Robert Plomin wants educators to take notice of genes, and has a new big idea – personalised learning.”

Fruit-loving lemurs score higher on spatial memory tests“Food-finding tests in five lemur species show that fruit-eaters may have better spatial memory than lemurs with a more varied diet. The results support the idea that relying on foods that are seasonally available and far-flung gives a competitive edge to individuals with certain cognitive abilities — such as remembering where the goodies are.”

What Does Our DNA Say About How We Look?“A biologist aims to profile suspects from genetic material left at crime scenes.’ – h/t matthew wygant!

Four Lame Responses to Sam Harris’ Moral Landscape Challenge“Moral emotions, like every other evolved trait, exist because their presence increased the probability that the genes responsible for the existence of those traits would survive and reproduce. Moral emotions, and the associated illusions of the existence of Good and Evil as things in themselves, exist as subjective impressions in the minds of individuals.” – from helian.

Free will beliefs and motivation to punish“In a paper forthcoming in the Journal of Personality and Social Psychology, Cory J. Clark and co-authors provide evidence that widespread belief in the existence of free will is bolstered by a fundamental desire to punish wrongdoers…. As Clark et al. put it, ‘There seems little doubt that the subjective experience of choosing and acting supports people’s belief in free will, but our findings suggest another powerful motivating factor: the human impulse to blame and punish. People believe in free will – at least in part – because they wish to affirm that people who do immoral things could have and should have acted differently’.”

A small contribution to the free-will thingy – from elijah.

Is there a ‘dark intelligence’? Emotional intelligence is used by dark personalities to emotionally manipulate others“Narcissism and psychopathy increased link between emotional intelligence facets and emotional manipulation.” – h/t claire lehmann!

Theory of mind: did evolution fool us?“Although sophisticated ToM is believed to have high adaptive fitness, broad experimental evidence from behavioural economics, experimental psychology and linguistics point towards limited recursivity in representing other’s beliefs.” – h/t neuroskeptic!

Creativity and personality in classical, jazz and folk musicians“[J]azz musicians are more frequently engaged in extracurricular musical activities, and also complete a higher number of creative musical achievements. Additionally, jazz musicians show higher ideational creativity as measured by divergent thinking tasks, and tend to be more open to new experiences than classical musicians. This study provides first empirical evidence that jazz musicians show particularly high creativity with respect to domain-specific musical accomplishments but also in terms of domain-general indicators of divergent thinking ability that may be relevant for musical improvisation.” – h/t mary louise cowan!

Migration and interaction in a contact zone: mtDNA variation among Bantu-speakers in southern Africa“In this study, we analyze complete mtDNA genome sequences from over 900 Bantu-speaking individuals from Angola, Zambia, Namibia, and Botswana to investigate the demographic processes at play during the last stages of the Bantu expansion. Our results show that most of these Bantu-speaking populations are genetically very homogenous, with no genetic division between speakers of Eastern and Western Bantu languages. Most of the mtDNA diversity in our dataset is due to different degrees of admixture with autochthonous populations.”

Silver Blaze“[I]n most parts of Europe, it looks as if modern populations inherited the three EEF/WHG/ANE groups (Levantine farmers, West Hunters and Sibermen) via only two proximate ancestral populations. Europe at the time was almost entirely occupied by Sardinian-like farmers – then another population moved in, one that had about 3 times as much West Hunter as Sibermen.” – from greg cochran.

Replacement or continuity?“Ancient DNA seems to promise a clearer picture because the only source of uncertainty is the age of the skeletal material. Unfortunately, this new method is more sensitive to uncertainty from another source: natural selection. Late hunter-gatherers and early farmers had to adapt to different environments. There certainly was a genetic divide between the two, but did it result from differences in origin or from differences in natural selection?” – from peter frost.

Dystopian diversity – from the awesome epigone.

“I regret studying social anthropology” – me, too. *sigh* – see also the original post.

The parasite that escaped out of Africa: Tracing origins of malaria parasite“An international team has traced the origin of the second-worst malaria parasite of humans to Africa. The closest genetic relatives of human *Plasmodium vivax* were found only in Asian macaques, leading researchers to believe that *P. vivax* originated in Asia. This study overturns that, finding that wild-living apes in central Africa are widely infected with parasites that, genetically, are nearly identical to human *P. vivax*.” – h/t hbd bibliography!

Are Rich People Really That Selfish? – New Queendom.com Study Looks At Impact of Socio-Economic Status on Altruistic Tendencies“‘Our personality impacts every aspect of our life – the choices we make, the people we surround ourselves with, the career we pursue, the way we respond to life experiences, the way we manage our finances, and whether or not we share our good fortune,’ explains Dr. Jerabek, president of the company…. [H]ow individuals conduct themselves when they have money has everything to do with who they are as a person. Money doesn’t make a person more or less selfish. If you are a genuinely kind and giving person, you’ll continue to be that way no matter how many zeros are on your paycheck.’”

Babies born in England and Wales to non-UK born mothers infographic“Total Fertility Rate in England/Wales by where mother born: 4.3 Afghanistan, 3.8 Pakistan, 3.3 Nigeria, 2.4 India, 1.8 UK.”

The Tale of a CRISPR Clone – from razib.

Graft Probe in Scientific Community Widens in Southern China“A corruption probe has so far snared more than 50 scientists and research administrators in Guangdong, one of China’s wealthiest provinces.”

Quick Winter Olympics Digit Ratio Note – from sisyphean the mad contrarian.

Scientist proposes revolutionary naming system for all life on Earth“…a naming convention based on genome sequencing to enhance the way organisms are classified.” – h/t super mario!

Burials uncovered in Ireland reflect fusion of Paganism and Christianity“Excavations at Caherconnell in County Clare, Ireland, have uncovered ancient burials that reflect a fusion of Pagan practices with Christianity. Although it was initially believed that Christianity was well established in Ireland by the 5th Century, the latest finding reveals that Celtic Paganism was not quick to die out.” – h/t derek hopper!

The Society of Mutual Autopsy“The Society of Mutual Autopsy was an organisation formed in the late 1800s to advance neuroscience by examining dead members’ brains and to promote atheism by breaking sacred taboos.”

Heavy metal bands per 100,000 people – global map.

A Campus More Colorful Than Reality: Beware That College Brochure – h/t conrad hackett! who tweeted: “The whiter the college, the more diversity depicted in the brochures.”

bonus: Confirmed: Oldest Fragment of Early Earth is 4.4 Billion Years Old

bonus bonus: Hubble Finds Possible Oldest Object Ever Seen“The Hubble Telescope’s new set of Frontier Fields images includes a galaxy some 13-billion light-years away, which makes it a candidate for the most distant object ever seen.”

bonus bonus bonus: Rust Cohle, Guidance Counselor – heh. (~_^)

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Calcium absorption not the cause of evolution of milk digestion in Europeans“‘The evolution of lactase persistence is one of the best known and most dramatic examples of recent human evolution. One of the ironies of working in this area is that we know it happened but we still don’t fully know why’ says Sverrisdóttir. Lactase persistence is found at highest frequencies in southern Sweden and in Ireland. Given that calcium absorption is not the only reason why this trait evolved so rapidly, Sverrisdóttir and colleagues have proposed another cause: Although most early European farmers would not have been lactase persistent, they would still have been able to consume fermented milk products such as yoghurt and cheese, because fermentation converts much of the lactose into fats. But in famine conditions, such as when crops fail, they are likely to have eaten all the fermented milk foods, leaving only the more high-lactose products. This would have caused the usual lactose intolerance symptoms such as diarrhea. Diarrhea in in healthy people is not usually life-threatening, but in severely malnourished individuals it certainly can be. So famine could have led to episodes of very strong natural selection favoring lactase persistence.”

Human and Helicobacter pylori coevolution shapes the risk of gastric disease“Patients were recruited from two geographically distinct Colombian populations with significantly different incidences of gastric cancer, but virtually identical prevalence of H. pylori infection. All H. pylori isolates contained the genetic signatures of multiple ancestries, with an ancestral African cluster predominating in a low-risk, coastal population and a European cluster in a high-risk, mountain population. The human ancestry of the biopsied individuals also varied with geography, with mostly African ancestry in the coastal region (58%), and mostly Amerindian ancestry in the mountain region (67%). The interaction between the host and pathogen ancestries completely accounted for the difference in the severity of gastric lesions in the two regions of Colombia. In particular, African H. pylori ancestry was relatively benign in humans of African ancestry but was deleterious in individuals with substantial Amerindian ancestry. Thus, coevolution likely modulated disease risk, and the disruption of coevolved human and H. pylori genomes can explain the high incidence of gastric disease in the mountain population.”

Seeing X Chromosomes in a New Light“X-chromosome inactivation, Dr. Nathans’s pictures show, creates a genetic diversity that’s particularly dramatic. Two cells side by side may be using different versions of many different genes. ‘But there is also much larger-scale diversity,’ Dr. Nathans said. In some brains, for example, a mother’s X chromosome was seen dominating the left side, while the father’s dominated the right. Entire organs can be skewed toward one parent. Dr. Nathans and his colleagues found that in some mice, one eye was dominated by the father and the other by the mother. The diversity even extended to the entire mouse. In some animals, almost all the X chromosomes from one parent were shut; in others, the opposite was true.”

Are plants altruistic?“Roots can distinguish self from other, and they know their own kind (species), they can share resources and information about insect attacks and deliver nutrients to trees in need. The preponderance of evidence does seem to suggest that plants are proactive in filling their own needs and the needs of others.” – ooooh, not just their own species, their own close relatives! – see also The Intelligent Plant.

Sluggish metabolisms are key to primates’ long lives“[P]rimates expend 50 per cent less energy than other mammals of equivalent mass during an average day. ‘What’s more, he says the difference is not easily explained by differing activity levels: a human would need to run a whole marathon every day to be on an even energetic footing with mammals that aren’t primates….’ The finding offers a completely new way to understand why primates have slower life histories than other mammals of equivalent body size…. Pontzer thinks that the slower metabolism may have evolved to help primates cope with food shortages. For instance, orang-utans suffer frequent famines. ‘Orang-utans experience extended periods of low fruit availability,’ says Vogel. ‘There are months when caloric intake is less than expenditure – and they burn body fat stores.’ A slow metabolism might help them survive.”

Triune origins“With the latest paper, the story on European origins is becoming clearer. Three populations account for European ancestry: the Mesolithic hunter-gatherers of western Europe (dubbed WHG in the paper), early European farmers derived from somewhere in the Mideast (EEF), and a third group more closely related to ancient Siberians (ANE) than any existing population. Those Sibermen also contributed a third of Amerindian ancestry, the rest being similar to modern East Asian populations.” – from greg cochran.

The first industrial revolution“As early modern humans spread farther north, they entered more challenging environments…. Did these new cognitive demands have an evolutionary impact? Did they select for certain mental capacities over others? Piffer (2013) has addressed these questions by seeing how hunter-gatherers differ from farming peoples in alleles at COMT, a gene linked to executive function, working memory, and intelligence…. Northern hunting peoples, however, differ from other hunter-gatherers and resemble more advanced farming populations.” – from peter frost.

‘Out of Africa’ gene mutation in human pigmentation increases predisposition to skin cancer“The V60L mutation is more common in people with light hair and skin tone that, despite being light, tans easily in the summer. This mutation is positive for the climate of the Mediterranean region, as it facilitates the absorption of vitamin D in the winter months, in which the ultraviolet radiation is lower. In the summer months, in which the radiation is greater, the ease to darken the skin pigmentation provides a certain protection. However, the study also revealed that among people with this mutation there is a greater predisposition to skin cancer.” – see also: Simultaneous Purifying Selection on the Ancestral MC1R Allele and Positive Selection on the Melanoma-Risk Allele V60L in South Europeans.

Longitudinal four-dimensional mapping of subcortical anatomy in human development – h/t kevin mitchell! who said: “Large imaging study details substantial sex differences in maturation dynamics of subcortical structures.” – also: Fundamental sex difference in human brain architecture [behind paywall].

Changes in Thickness and Surface Area of the Human Cortex and Their Relationship with Intelligence“At 10 years of age, more intelligent children have a slightly thinner cortex than children with a lower IQ. This relationship becomes more pronounced with increasing age: with higher IQ, a faster thinning of the cortex is found over time. In the more intelligent young adults, this relationship reverses so that by the age of 42 a thicker cortex is associated with higher intelligence. In contrast, cortical surface is larger in more intelligent children at the age of 10. The cortical surface is still expanding, reaching its maximum area during adolescence. With higher IQ, cortical expansion is completed at a younger age; and once completed, surface area decreases at a higher rate. These findings suggest that intelligence may be more related to the magnitude and timing of changes in brain structure during development than to brain structure per se, and that the cortex is never completed but shows continuing intelligence-dependent development.”

Why do spatial abilities predict mathematical performance?“About a third of the variation in spatial ability at age 12 is explained by genetic factors; a little less than half of the variation in mathematics at this age is genetic. We find no sex differences in the genetic and environmental influences (either in magnitude or type) on mathematical and spatial variation at age 12. The observed overlap between spatial ability and mathematics is substantial (r > .40). Approximately 60% of this overlap is explained by common genetic effects, with 40% of the overlap due to environmental experience.” – h/t DOCTOR stuart ritchie! (^_^)

New evidence shows the FDA was wrong to halt 23andMe testing“While the tests are often too inaccurate for consumers to consider them diagnoses, research shows that most customers will seek a doctor’s opinion before taking action, anyway. According to the authors’ research, 58% of 1,051 surveyed customers did nothing at all with their genomic results. Of the 42% who made health decisions based on the information, only 2% changed prescription drug regimens without consulting a physician. The majority of customers who made changes focused on diet, exercise, and vitamins.”

Dogs’ Closest Wolf Ancestors Went Extinct, Study Suggests” A new genetic analysis of modern dogs and wolves suggests that man’s best friend was domesticated before agriculture. But the origin of this domestication remains stubbornly mysterious. Researchers analyzed the genomes of wolves from three likely sites of domestication (the Middle East, Asia and eastern Europe), and found that modern dogs were not more closely related to any of the three. In fact, it seems that the closest wolf ancestors of today’s dogs may have gone extinct, leaving no wild descendants.” – also: Paedomorphic Facial Expressions Give Dogs a Selective Advantage – woof! – h/t claire lehmann!

The Nurture Enigma – How Does the Environment Influence Human Nature? – from staffan.

The interplay of genetic and cultural evolution – from jason collins.

Eye of the Tiger PeopleBut what the hell is ‘culture,’ anyway? Talk about a social construct! Even the term ‘social construct’ is a social construct, one unique to our culture. And who’s to say culture is entirely separate from genetics? There’s some suggestion that the two may be intimately intertwined. In rawest terms, ‘culture’ may be nothing more than what happens when a group’s genes interact with their environment. – from jim goad.

Toddlers’ aggression is strongly associated with genetic factors, study reports“The development of physical aggression in toddlers is strongly associated genetic factors and to a lesser degree with the environment, according to a new study led by Eric Lacourse of the University of Montreal and its affiliated CHU Sainte-Justine Hospital. Lacourse’s worked with the parents of identical and non-identical twins to evaluate and compare their behaviour, environment and genetics.” – h/t mr. mangan, esq!

Modifying DNA May Wipe Away Old Memories – so can several double gin and tonics in a row. (~_^) – they’re talking about epigenetic changes here, btw.

Apes are intuitive statisticians“Here, we conducted the first investigation of such intuitive statistical reasoning with non-human primates. In a series of 7 experiments, Bonobos, Chimpanzees, Gorillas and Orangutans drew flexible statistical inferences from populations to samples. These inferences, furthermore, were truly based on statistical information regarding the relative frequency distributions in a population, and not on absolute frequencies. Intuitive statistics in its most basic form is thus an evolutionarily more ancient rather than a uniquely human capacity.” – iow, the other great apes outperform a lot of humans (i.e. the pc ones)! (~_^) – h/t neuroskeptic!

Study: Chimpanzees Bond Over Shared Meals“[C]himps who share their food have higher levels of oxytocin, known as the love hormone, than those who don’t.” – h/t hbd bibliography!

Comedians have psychotic personality traits, study finds“In a study in the British Journal of Psychiatry, researchers analyzed comedians from Australia, Britain and the United States and found they scored significantly higher on four types of psychotic characteristics compared to a control group of people who had non-creative jobs. The traits included a tendency towards impulsive or anti-social behavior, and a tendency to avoid intimacy. ‘The creative elements needed to produce humor are strikingly similar to those characterizing the cognitive style of people with psychosis – both schizophrenia and bipolar disorder,’ said Gordon Claridge of the University of Oxford’s department of experimental psychology, who led the study.”

Natural selection can favour ‘irrational’ behaviour – well, there’s your problem!

‘Human evolution likely led to rise of religion’ – h/t holly dunsworth! whose response was: duh! (~_^)

New study finds mistimed sleep disrupts rhythms of genes in humans“During this disruption of sleep timing, there was a six-fold reduction in the number of genes that displayed a circadian rhythm (a rhythm with an approximately 24 hour period). This included many regulators associated with transcription and translation, indicating widespread disruption to many biological processes.” – sleep right!

speaking of which: Study finds later school start times improve sleep and daytime functioning in adolescents – h/t anatoly!

The human brain can process images the eye sees for 13 milliseconds – imagine how quickly THE FLASH’s brain can process images!! (~_^)

The Islamic Republic of Baby-Making“Iran, like other Middle Eastern countries, has an extremely high infertility rate. More than 20 percent of Iranian couples cannot conceive, according to a study conducted by one of the country’s leading fertility clinics, compared with the global rate of between 8 and 12 percent. Experts believe this is due to the prevalence of consanguineous marriages, or those between cousins. Male infertility is ‘the hidden story of the Middle East,’ says Marcia Inhorn, a Yale University medical anthropologist and a specialist on assisted reproduction in the region.”

This Language Names Odors As Precisely As English Speakers Name Colorjahai speakers in malaysia. – h/t t.greer! – see also: Can You Name That Smell?“It’s also possible that the Jahai are built differently than the rest of us. The genes that code for the olfactory receptors in our noses exhibit a great deal of variation not only between different human populations but also between people. So it may be that the Jahai have evolved more of these receptors or a greater diversity of them than everyone else, much like the Tsimane tribe from the Bolivian rainforest were shown to be more sensitive to smells than were Germans.”

Gene therapy ‘could be used to treat blindness’“Surgeons in Oxford have used a gene therapy technique to improve the vision of six patients who would otherwise have gone blind. The operation involved inserting a gene into the eye, a treatment that revived light-detecting cells.”

The thinnest Americans are Asian Americans, CDC data show – surprise!

Shapely centrefolds? Temporal change in body measures: trend analysis – h/t ben southwood! who said: “Playboy centrefolds’ waists have widened, weights have fallen, busts have shrunk and hips have narrowed since 1953.”

Study: Violence, infectious disease and climate change contributed to Indus civilization collapse – h/t mike anissimov!

What was in that grog? Scientists analyze ancient Nordic drink“Ancient Scandinavians quaffed an alcoholic mixture of barley, honey, cranberries, herbs and even grape wine imported from Greece and Rome, new research finds.” – mmmmmm! mmmmmm?

bonus: i’m a journalist! – h/t jayman!

bonus bonus: and a neo-fascist, too, apparently. hahahahahahahaha!! *snort*

bonus bonus bonus: Genetically engineered plant glows so brightly it can be used as a LAMP

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i linked to this paper…

Friendship and Natural Selection

…in this past sunday’s linkfest, but, to be honest with you, i hadn’t actually read it. (yeah, i do that sometimes. ok, ok — a LOT of times!)

since then, a couple of people urged me to read the arXiv blogpost on it (thanks @DKshad0w and @SamoBurja!), which prompted me to read the orig. research paper and … wow! … mind. blown.

now, no, i’m NOT a geneticist — i don’t even play one on the innerwebs — so i’m not your gal for evaluating whether or not these guys — nicholas christakis and james fowler — have done their work right, but if they have, this is very cool stuff:

- Pairs of friends are, on average, as genetically similar to one another as fourth cousins, which seems noteworthy since this estimate is net of mean ancestry and background relatedness.”

fourth cousins! note that these are (i believe) all white folks. the data are from the framingham heart study, but the researchers do say that they controlled both for relatives (i.e. that individuals might be “friends” with people who are, in fact, distant relatives) and ethnicity (eg. that italians might just be friends with other italians).

- It is intriguing that genetic structure in human populations may result not only from the formation of reproductive unions, but also from the formation of friendship unions. This in turn has relevance for the idea of an evocative gene-environment correlation, proposed more than 30 years ago, which suggests that a person’s genes can lead one to seek out circumstances that are compatible with one’s genotype. Our results suggest that these circumstances could include not only the physical environment but also the *social* environment, and hence the genotypic constitution of one’s friends. As Tooby and Cosmides argue, ‘not only do individual humans have different reproductive values that can be estimated based on various cues they manifest, but they also have different association values.’ People may seek out particular, convivial social environments that affect their fitness.

i’ve been saying for a while now that the family types/social structures in which individuals are located ought to be taken into consideration when thinking about the fitness of those individuals and how natural selection might be working on different individuals living and reproducing in different sorts of social structures (individuals living in nuclear family structures versus large clan structures, for instance). i’ve mostly been thinking about family structures, but christakis and fowler are talking about friendship structures — alliances with non-family members. cool!

- “The existence of excess genetic similarity between friends is also relevant to the growing area of indirect genetic effects, wherein the phenotypic traits of focal individuals are influenced by the genomes of their neighbors, in a kind of ‘network epistasis.’ In fact, our results support the idea that humans might be seen as metagenomic not just with respect to the microbes within them, but also with respect to the humans around them. It may be useful to view a person’s genetic landscape as a summation of the genes within the individual and within the people surrounding the individual, just as in certain other organisms.

yeah. just muse on THAT for a while. (~_^) and then try this on for size…

- “[T]he human evolutionary environment is not limited to the physical environment (sunshine, altitude) or biological environment (predators, pathogens), but also includes the social environment, which may itself be an evolutionary force. Our finding that positively correlated genotypes are under positive selection suggests that the genes of other people might modify the fitness advantages of one’s own genes, thus affecting the speed and outcome of evolution.

did you get that? the researchers found that, the SNPs that were most common between the friends (the homophilic SNPs), have, indeed, been under recent positive selection:

“To test the hypothesis that homophilic SNPs are generally under recent positive selection, we use the Composite of Multiple Signals (CMS) score. This score combines signals from several measures of positive selection to create a single value that indicates the likelihood a SNP has been increasing in frequency due to selection pressure over the last 30,000 years (see SI). In Fig.3, we show that, after correcting for correlated outcomes due to linkage disequilibrium and for varying precision in the GWAS estimates (see SI), the top 20% most homophilic SNPs have significantly higher CMS scores than the other 80% (+0.07, SE 0.02, p = 0.003)…. In contrast, Fig.3 also shows that CMS scores are not significantly higher for the most homophilic SNPs in the strangers GWAS (–0.00, SE 0.02, p = 0.86). This suggests that the whole-genome regression model we use does not generate false positives…. In sum, it appears that, overall, across the whole genome, the genotypes humans tend to share in common with their friends are more likely to be under recent natural selection than other genotypes.

friendship and natural selection 01

friendship and natural selection 02
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with human biodiversity in mind, my question would be: do all peoples everywhere form an equal number of friendships with (technically) unrelated individuals? yes, i have an obsession with clannish peoples — but, seriously — do people who live in clans or tribes make as many “friends” as peoples who don’t? do they even have the opportunity? if not, what might this mean for natural selection in those populations?

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Inbred royals show traces of natural selection“Study suggests the Spanish Habsburgs evolved to mute the effects of inbreeding, but other geneticists are unconvinced.”

Time to get tough on the physiological causes of crime“[V]iolent criminals are biologically different from the rest of us.” – review of The Anatomy of Violence: The Biological Roots of Crime.

Scientists find ethnicity linked to antibodies“‘[I]t’s early days,’ emphasizes Watson, ‘but these findings could mean that past environmental exposures to certain pathogens caused DNA insertions or deletions in different ethnic groups, which could impact disease risk. Our results demonstrate that antibody studies need to take into account the ethnicity of DNA samples used.’”

Those resistant to ‘love hormone’ may also be easier to hypnotize“Gene variants linked to social detachment may increase suggestibility.”

One Blessing Of Outbreeding – i didn’t write this, i swear! (you’ll never guess who did…)

The gay germ hypothesis – from peter frost. see also Not Final! from greg cochran.

Another reminder…“[A] prod to certain of my smart liberal friends to start having children.” – from jayman. see also: The end of paternal investment or, more cads, fewer dads from mr. mangan.

The Strange Case of Dr. Robert Trivers“[Trivers] has been driven off the campus of Rutgers University! He has been involved in a controversy lately over his accusation that one of his graduate students committed fraud in a scientific paper. Apparently he was banned from campus because a colleague who supports the alleged fraudster claimed Trivers had ‘frightened him in his office’.” – from helian unbound.

Women graduates of elite colleges 1/3rd more likely to be stay-at-home moms – from steve sailer.

Scent of a Man: Women Can Sniff Out a Hot Guy“Women at their peak fertility prefer the smell of men oozing with testosterone, a new study finds.” – and speaking of testosterone: Testosterone pumps up threats for tough guys“The higher a man’s testosterone level, the more macho he’s likely to act when his masculinity is threatened, a new study finds.”

The Real ‘Hobbit’ Had Larger Brain Than Thought

Egyptian mummies yield genetic secrets“The ancient Egyptians could soon be getting their genomes sequenced as a matter of routine.”

Why Menopause?

Stonehenge occupied 5,000 years earlier than thought

The Pattern of Female Nuptiality in Oman“[M]ore than half (52%) of the total marriages in Oman are consanguineous. First cousin unions are the most common type of consanguineous unions, constituting 39% of all marriages and 75% of all consanguineous marriages. About 11% of the marriages are polygynous…. [P]aternal first-cousin marriages constituted 27.7% of all marriages and 72% (565/786) of all first-cousin marriages, while maternal first-cousin marriages constituted 10.8% of all marriages and 28% (221/786) of all first-cousin marriages.”

The Ancient Greeks & Romans, Beauty and Human Biodiversity – @occam’s razor.

Could Life Be Older Than Earth Itself?“[T]wo geneticists have applied Moore’s Law to the rate at which life on Earth grows in complexity — and the results suggest organic life first came into existence long before Earth itself.”

Chimps Communicate Like Passionate Italians – my favorite headline of the week. (^_^)

Live fast, die younger: Actors, singers and sportsman ‘die seven and a half years before other high achievers’

Historic human remains yield epigenetic tags – see also: Epigenetic Inheritance: Fact or Fiction?

Icelandic anti-incest app keeps residents from becoming kissin’ cousins – previously íslendingabók.

‘Real men wear kilts’: The anecdotal evidence that wearing a Scottish kilt has influence on reproductive potential: how much is true? – keep wearin’ yer kilt!

Did this magical little crystal help the Vikings rape and pillage across the world?“Research suggests crystal salvaged from a shipwreck may be a sunstone”

bonus: What rights should Dzhokhar Tsarnaev get and why does it matter?“The Obama DOJ says it intends to question the Boston bombing suspect ‘extensively’ without first Mirandizing him”

bonus bonus: Applicants wanted for a one-way ticket to Mars – let’s go! (^_^)

bonus bonus bonus: ‘Living fossil’ genome unlocked“The genes of an ancient fish, the coelacanth, have much to reveal about our distant past.”

bonus bonus bonus bonus: Chlamydia Is Killing Koalas — Will Genetics Find a Cure?

(note: comments do not require an email. ugly fish!)

extra-long [insert dongle joke here] linkfest this week since there wasn’t one last sunday (sorry, dog ate it…). note that there (probably) won’t be one next sunday either, ’cause i’ll be too busy hunting for easter eggs…. (^_^)

Common DNA Markers Can Account for More Than Half of the Genetic Influence on Cognitive Abilities“In the same sample of 3,154 pairs of 12-year-old twins, we directly compared twin-study heritability estimates for cognitive abilities (language, verbal, nonverbal, and general) with GCTA estimates captured by 1.7 million DNA markers. We found that DNA markers tagged by the array accounted for .66 of the estimated heritability, reaffirming that cognitive abilities are heritable. Larger sample sizes alone will be sufficient to identify many of the genetic variants that influence cognitive abilities.” – via race/history/evolution notes.

Genotypes over-represented among college students are linked to better cognitive abilities and socioemotional adjustment“The present study investigated … genotype frequencies of 284 SNPs covering major neurotransmitter genes in a sample of 478 Chinese college students, comparing these frequencies with those of a community sample (the 1000 Genomes dataset)…. Results showed that 24 loci showed Hardy–Weinberg disequilibrium among college students, but only two of these were in disequilibrium in the 1000 Genomes sample. These loci were found to be associated with mathematical abilities, executive functions, motivation, and adjustment-related behaviors such as alcohol use and emotion recognition.” – via … somebody … can’t remember who. sorry!

Genes and Smarts – from the derb.

Why Bacteria Commit Suicide“[I]nfected individuals self-destructed before they could spread the virus to others.”

Evolution via Roadkill“Cliff swallows that build nests that dangle precariously from highway overpasses have a lower chance of becoming roadkill than in years past thanks to a shorter wingspan that lets them dodge oncoming traffic. That’s the conclusion of a new study based on 3 decades of data collected on one population of the birds. The results suggest that shorter wingspan has been selected for over this time period because of the evolutionary pressure put on the population by cars.”

‘Out of Africa’ Story Being Rewritten Again“Our early human ancestors may have left Africa more recently than thought, between 62,000 and 95,000 years ago, suggests a new analysis of genetic material from fossil skeletons.” – see also Mitochondrial DNA tree calibrated with ancient DNA @race/history/evolution notes and Revised timescale of human mtDNA evolution from dienekes.

How Social Darwinism Made Modern China“A thousand years of meritocracy shaped the Middle Kingdom.” – good stuff from ron unz. see also the derb and peter frost and anatoly.

Does the Clark-Unz model apply to Japan and Korea? – from peter frost.

Did evolution give us inflammatory disease?“[S]ome variants in our genes that could put a person at risk for inflammatory diseases such as multiple sclerosis, Crohn’s disease or rheumatoid arthritis, have been the target of natural selection over the course of human history.” – original research article.

Genes may be reason some kids are picky about food“The study looked at 66 pairs of twins between ages 4 and 7 years old, and found that genes explain 72 percent of the variation among children in the tendency to avoid new foods, while the rest was influenced by environment.”

A Tale of Three Maps – from jayman.

Dan Freedman’s babies and National Character – from greg cochran @west hunter (buy the e-book!).

HVGIQ: The Bahamas – from jason malloy.

The Personality of Tribalism – from staffan.

Remembering Stephen Jay Gould: Bully and Boob – from steve sailer.

Depicting reality or escaping from it? – the awesome epigone asks a good question/makes a good point about something in steven pinker’s Better Angels.

Assortative mating and shared life history strategy – from mr. mangan.

Uh-Oh… – malcolm pollack on why there’s not so much “diversity” in silicon valley: “It’s because Silicon Valley … *is* a meritocracy — you just can’t fake being good at writing code, solving complex engineering problems, or designing high-tech gadgetry….”

Was inbreeding common among early humans? 100,000-year-old deformed skull adds evidence to theory of ‘very small’ communities“The discovery adds to growing evidence that early humans inbred often” – prolly because populations were small. see also Abnormalities in Pleistocene Homo from dienekes.

Moral Matter – the neuroscience of morality.

Crime and punishment: From the neuroscience of freewill to legal reform

Men programmed to avoid sex with best friends’ wives: study“Researchers suggest guys may have a biological predisposition against hitting on their best friends’ partners…. A University of Missouri study has found that adult males’ testosterone levels dropped when they were interacting with the marital partner of a close friend.”

Downton Abbey: Earl of Grantham maximizes inclusive fitness – @occam’s razor.

Experts Say Food May Contribute To Anger, Violent Behavior“Pace and other nutritionists say if you eat plenty of fish, eggs, beans, fruits and green leafy vegetables, you should have the nutrients you need. However, people who tend to eat a diet loaded with processed or packaged foods could find themselves more easily irritated.”

Women abused as children likelier to bear autistic child

One of Us – animals are people, too.

Text mining uncovers British reserve and US emotion“An analysis of the digitized texts of English-language books over the past century concludes that, since the 1980s, words that carry emotional content have become significantly more common in US books than in British ones.”

Evolution and Existentialism, an Intellectual Odd Couple“On the basis of evolutionary existentialism, I would therefore like to suggest the heretical and admittedly paradoxical notion that, in fact, we need to teach more disobedience. Not only disobedience to political and social authority but especially disobedience to some of our troublesome genetic inclinations.” – hmmmm….

Forbidden City“The left-wing stranglehold on academia.”

bonus: Life found deep under the sea“Oceanic-crust microbes survive on hydrogen and carbon dioxide.” in other microbial news: Mariana Trench: Deepest ocean ‘teems with microbes’“The deepest place in the ocean is teeming with microscopic life, a study suggests.”

bonus bonus: Palestinian Mother Speaks Out About Daughter’s Honor Killing“[H]onor killing defendants [are] usually given light sentences. Three years in prison was the stiffest in these cases. Life sentences or execution were never a consideration…. Offenders receive reduced sentences pursuant to Article 18 of Penal Code no. 74 of 1936, which is entitled ‘Necessity.’ The article provides for ‘leniency in punishment for crimes that offenders have committed in order to avert consequences, which could cause irreparable damage to their honor, money, or the honor of those such offenders are obliged to protect.’”

bonus bonus bonus: The Hate List“[T]he [$]PLC’s site explains that it counts counted ’1,007 active hate groups in the United States in 2012,’ including ‘organizations and their chapters.’ But ‘The Year in Hate and Extremism’ did not make the ‘chapter’ distinction explicit. It is rarely drawn out in the organization’s frequent media appearances, nor was it mentioned in a letter from the SPLC to the Justice Department warning of the growing threat.” – see also What’s hate got to do with it? @bad data, bad!

bonus bonus bonus bonus: Amazing photographs reveal the lost world of the Omo tribes of Ethiopia

bonus bonus bonus bonus bonus: A Tiny Village Where Women Chose to Be Single Mothers“30 years ago in this bucolic village in northern Vietnam, the fierce determination of one group of women to become mothers upended centuries-old gender rules….”

bonus bonus bonus bonus bonus bonus: Cannibals of the Past Had Plenty of Reasons to Eat People

bonus bonus bonus bonus bonus bonus bonus: Phallus-shaped fossils identified as new species [insert dongle joke here]

bonus bonus bonus bonus bonus bonus bonus bonus: Global Internet Porn Habits Infographic – ‘sup finnish people?! and romanians and hungarians (“mom and son”?!)?!

bonus bonus bonus bonus bonus bonus bonus bonus bonus: i love the ukrainian parliament. no, i really do! (~_^)

(note: comments do not require an email. double dongle.)

“If during the long course of ages and under varying conditions of life, organic beings vary at all in the several parts of their organisation, and I think this cannot be disputed; if there be, owing to the high geometrical powers of increase of each species, at some age, season, or year, a severe struggle for life, and this certainly cannot be disputed; then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of existence, causing an infinite diversity in structure, constitution, and habits, to be advantageous to them, I think it would be a most extraordinary fact if no variation ever had occurred useful to each being’s own welfare, in the same way as so many variations have occurred useful to man. But if variations useful to any organic being do occur, assuredly individuals thus characterised will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offspring similarly characterised. This principle of preservation, I have called, for the sake of brevity, Natural Selection.”

- Chas. Darwin, On the Origin of the Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for Life (1859), pgs. 126-27.

nice!

(note: comments do not require an email. finches.)

working hypothesis: that the medieval period was a d*mned interesting time wrt selection pressures on europeans (and by europeans i mostly mean northern europeans, altho interesting stuff undoubtedly happened in the south, too) and a lot of the genes for the characteristics we associate with h. europaeus were selected for during this time period.

i know — it’s a long time period, but that doesn’t make it any the less interesting or remarkable.

you’ve got:

- the ashkenazi jewish iq thing [opens pdf], a la cochran, laurel and hardy, and harpending. (you might quibble that they’re not really europeans — ashkenazi jews, that is, not cochran, et. al. my point is, tho, that their high average iq — the ashkenazis, that is — seems to have been selected for in medieval europe.)

- the middle class traits and general independent spirit of the english (and possibly other northern europeans) prolly being selected for starting in the medieval period.

- the shift from tribes to not-tribes via the changing mating patterns which prolly impacted altruism genes amongst other behavioral traits.

- manoralism. not sure what traits might’ve been selected for due to the manoralism system in europe. for one thing, the manors, along with the church, contributed to the, relatively speaking, genetic unrelatedness within some european populations. that the manor system never really took hold in places like greece and italy (according to mitterauer) might explain a lot about those populations. also, i’m guessing that manoralism — which wasn’t very powerful in england either (feudalism arrived quite late there, no?) — might’ve select for somewhat docile personalities. you know — individuals who will go along with what the masser (whether that be the monastery or the lord of the manor) or the group has to say rather than being fiercely independent? conformists, in other words. think: germans.

- the ostseidlung. the eastward expansion of germans (and others) in many cases within the manor system again. selective pressures?: for hard, efficient workers. again, not too uppity. high-ish iq?

- meanwhile, southern spain and italy had arab/north africa settlement and rule for a time. ireland and other “celtic fringe” areas ignored the church regulations on marriage and didn’t really adopt the manor system, either. eastern europe? who knows? (somebody other than me!)

- the black death.

new year’s resolution for 2012 (is it too early to make resolutions?): think and learn more about the selective pressures on european populations during the middle ages.

previously: and so my next question naturally is… and setting the stage

(note: comments do not require an email. think, think, think.)

in biology, altruism is defined as more than just lending the neighbor a cup of sugar. being altruistic means reducing one’s own fitness somehow (although i guess that one cup of sugar might, in some instances, be critical to one’s survival!), maybe passing up on a chance to reproduce or even sacrificing one’s own life for another.

seems like every creature on the planet displays some sort of altruistic behavior. plants put down fewer roots (presumably lowering their fitness) in the presence of related plants; some of the amoebas that live together as slime molds sacrifice their lives for their fellow single-celled family members; and, of course, the classic example of the eusocial insects — ants, bees, etc. — who have whole castes that do not reproduce and simply work their little hearts out raising their sisters (to whom they are more genetically related than they would be to their offspring — it’s complicated — don’t ask! or you can read about it here.). if you’re interested, there’s lots more about altruistic behaviors in animals in wikipedia.

my point is: there must be a whole range of altruism genes out there since all sorts of different creatures display all sorts of different altruistic behaviors. one size does not fit all.

furthermore, i’d be willing to bet the bank (hey — it’s not my money!) that there are different altruism genes in different human populations. or, at least, different frequencies of different altruism genes/alleles in different populations.

i’m sure there’s prolly plenty of overlap ’cause we’re all humans, primates, mammals, vertebrates, tetrapods, laurasians, etc., etc. but the various human populations have had quite unique evolutionary histories, so it shouldn’t be surprising if varying frequencies of/different altruism genes/alleles have been selected for here and there.

think of the fact that different genes for light skin color were selected for in europeans versus east asians and you’ll get my drift.

also think about how different peoples seem to display (at least somewhat) different altruistic behaviors. consider suicide bombers who, perhaps comparable to honey bees or g. sulphureus soldier termites who sacrifice themselves to defend their colonies, seem to be more common in some populations (middle eastern, japanese) than others (although maybe these examples are just artifacts of desperate circumstances).

“genes for suicide missions” won’t just pop up out of the blue, or very easily either i imagine. full hymenopteran sisters share 3/4s of their genes with each other, so it’s not surprising that they’re willing to sacrifice everything for their siblings. but it’s hard to see how such “extreme altruism” genes could arise in humans.

however, it is conceivable that, for example, in arab societies — tribal societies based upon a certain mating pattern (fbd marriage) which creates “bands of brothers” — over one thousand years of tribal warfare might’ve selected for a greater willingness to partake in kamikaze behaviors. remember that inbreeding means the evolution of altruism is easier.

it’s just a thought.

in any case, when we’re talking about genes for altruism, i think we should ask ourselves: which altruism genes?

edit: hamilton got here first, of course (^_^) [pgs. 19-20] -

“I do believe in the existence of considerable genetical differences in altruism, in selfishness, and in many other social attributes in most social animals, and this includes in humans, but this belief is certainly not predicated directly from kin-selection theory. Rather, it is underpinned more by a belief in a complexity of life sufficient to generate genetical variability in a almost everything — the variability we actually see — and also, as will appear in Volume 2 of this compilation, by modern theoretical expectations connected with reciprocation and with disease selection. It certainly does not come from kin selection per se.”

previously: genes for altruism

(note: comments do not require an email. my favorite altruism cartoon. [the only altruism cartoon?])

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