linkfest – 10/11/15

Ancient Ethiopian genome reveals extensive Eurasian admixture throughout the African continent“Here, we present a 12.5x coverage ancient genome of an Ethiopian male (‘Mota’) who lived approximately 4,500 years ago. We use this genome to demonstrate that the Eurasian backflow into Africa came from a population closely related to Early Neolithic farmers, who had colonized Europe 4,000 years earlier. The extent of this backflow was much greater than previously reported, reaching all the way to Central, West and Southern Africa, affecting even populations such as Yoruba and Mbuti, previously thought to be relatively unadmixed, who harbor 6-7% Eurasian ancestry.” – h/t john hawks! who tweeted: “First ancient DNA from Ethiopia shows that today’s sub-Saharan Africans are at least 0.2-0.7% Neanderthal ancestry!” – see also: First Ancient African Genome Reveals Vast Eurasian Migration“The man’s genome is, unsurprisingly, more closely related to present-day Ethiopian highlanders known as the Ari than to any other population the team examined, suggesting a clear line of descent for the Ari from ancient human populations living in the area. But further genetic studies show that the Ari also descend from people that lived outside Africa, which chimes with a previous study that discovered a ‘backflow’ of humans into Africa from Eurasia around 3,000 years ago.”

Eight thousand years of natural selection in Europe“The arrival of farming in Europe around 8,500 years ago necessitated adaptation to new environments, pathogens, diets, and social organizations…. We identify genome-wide significant signatures of selection at loci associated with diet, pigmentation and immunity, and two independent episodes of selection on height…. These results suggest that the modern South-North gradient in height across Europe is due to both increased steppe ancestry in northern populations, and selection for decreased height in Early Neolithic migrants to southern Europe. “

The Hybrid Origin of “Modern” Humans“Recent genomic research has shown that hybridization between substantially diverged lineages is the rule, not the exception, in human evolution. However, the importance of hybridization in shaping the genotype and phenotype of Homo sapiens remains debated. Here we argue that current evidence for hybridization in human evolution suggests not only that it was important, but that it was an essential creative force in the emergence of our variable, adaptable species.”

Neanderthal ‘flower children’ burials theory debunked“New research casts doubt on the idea that Neanderthals buried their dead covered in flowers.”

Intelligence in youth and health at age 50“Higher intelligence in youth is linked with better physical health at age 50.” – h/t andrew sabisky!

Chorionicity and Heritability Estimates from Twin Studies: The Prenatal Environment of Twins and Their Resemblance Across a Large Number of Traits“There are three types of monozygotic (MZ) twins. MZ twins can either share one chorion and one amnion, each twin can have its own amnion, or MZ twins can—like dizygotic twins—each have their own chorion and amnion. Sharing the same chorion may create a more similar/dissimilar prenatal environment and bias heritability estimates…. We conclude that the influence on the MZ twin correlation of the intra-uterine prenatal environment, as measured by sharing a chorion type, is small and limited to a few phenotypes.”

Genetic transmission of reading ability – h/t steve stewart williams! who tweeted: “If you want your kids to read, your best bet is to have kids with a reader.”

It All Began at Ararat, and Esau’s Revenge“Ancient DNA in Europe strongly indicates massive replacement [of hunter-gatherers by agriculturalists]. But, there is also suggestion of admixture with the local substrate. And, unlike the stylized model of Bellwood, it seems that there were multiple migrations after the initial pulse which reshaped the genetic and cultural landscape of human societies in the wake of agriculture.” – from razib.

Closing the Black-White IQ Gap Debate, Part I – from chanda chisala. and a response from peter frost: No, blacks aren’t all alike. Who said they were? – and previously on this blog: there’s more to human biodiversity than just racial differences.

The Association of Cognitive Ability with Right-wing Ideological Attitudes and Prejudice: A Meta-analytic Review“The present meta-analyses revealed an average effect size of r = −.20 [95% confidence interval (95% CI) [−0.23, −0.17]; based on 67 studies, N = 84 017] for the relationship between cognitive ability and right-wing ideological attitudes and an average effect size of r = −.19 (95% CI [−0.23, −0.16]; based on 23 studies, N = 27 011) for the relationship between cognitive ability and prejudice.”

[male] Chimps like boys toys too“If you want to know why young boys play with toy guns, you could do worse than consider why young male chimpanzees play with leaves and stones.” – h/t darren burke! who tweeted: “Western social constructivism is so insidious and widespread it is even affecting wild chimpanzees now!” – (~_^)

Ravens cooperate, but not with just anyone“Ravens detect cheaters in cooperation.”

Understanding the Cognitive and Genetic Underpinnings of Procrastination: Evidence for Shared Genetic Influences With Goal Management and Executive Function Abilities – procrastination (at least) 28% heritable. will have to read original paper. tomorrow, maybe. (~_^)

Personality Traits Increasingly Important for Male Fertility: Evidence from Norway“[P]ersonality relates to men’s and women’s fertility differently; conscientiousness decreases female fertility, openness decreases male fertility and extraversion raises the fertility of both sexes. Neuroticism depresses fertility for men, but only for those born after 1956.”

Host genetic variation impacts microbiome composition across human body sites“Our results highlight the role of host genetic variation in shaping the composition of the human microbiome, and provide a starting point toward understanding the complex interaction between human genetics and the microbiome in the context of human evolution and disease.”

DNA At the Fringes: Twins, Chimerism, and Synthetic DNA – h/t genetics and society! who tweeted: “Chimeras could undermine DNA forensics & use of DNAtesting as conclusive proof of crime & family.”

Ethnic differences in the association between depression and chronic pain: cross sectional results from UK Biobank [pdf] – h/t don lyall!

Emotion, rationality, and decision-making: how to link affective and social neuroscience with social theory

Women and men react differently to infidelity“While men are most jealous of sexual infidelity, women are most jealous of emotional infidelity.” – w.e.i.r.d. study. (n=1000).

‘Safe spaces’ exist because universities treat secular ideas as sacred“The most influential effect of this cultural and political imbalance is that academia has ignored the increasing evidence that human traits are heavily influenced by hereditary factors, most prominently in intelligence and sexual differences. This has a huge bearing on public policy, especially when so much of policy is involved in tackling inequality of various kinds. It would be like trying to reduce economic inequality while pretending that wealth cannot be inherited, because that’s offensive to people’s parents, and that all fortunes were the results of education, hard work or sheer luck.” – from ed west.

Relics of the Blank Slate, as Excavated at “Ethics” Magazine“There’s a reason that the Blank Slaters clung so bitterly to their absurd orthodoxy for so many years. If there is such a thing as human nature, then all the grandiose utopias they concocted for us over the years, from Communism on down, would vanish like so many mirages.” – from helian.

Anthropologist: “I’ve Never Been So Disgusted with My Own Data” – from steve sailer.

“Ethics” is advertising – david chapman on virtue signaling (trans: signalling. (~_^) ).

Two Fed economists tried to replicate some top economic studies — and the results are dreadful – from mike bird.

The shifting tide of American immigration – from colin woodard.

Missing piece of Gilgamesh Epic discovered

Pompeii Victims’ Bodies Revealed in [ct] Scans: Photos

Excavations at Mexican ruin site yields new details of Aztecs’ sacrifice of captured Spaniards“It was one of the worst defeats in one of history’s most dramatic conquests: Only a year after Hernan Cortes landed in Mexico, hundreds of people in a Spanish-led convey were captured, sacrificed and apparently eaten.”

bonus: Most worker ants are slackers“[N]ew research shows that many ants in a colony seem to specialize in doing nothing at all. To get a closer look at how these ants filled their time, researchers marked every member of five lab-based colonies with dots of colored paint. Over the course of 2 weeks, a high-definition camera recorded 5-minute segments of the ants in action six times a day, capturing their behavior (or lack thereof). Out of the ‘workers,’ 71.9% were inactive at least half the time, and 25.1% were never seen working. A small fraction of the ants, just 2.6%, were always active during observation, the researchers wrote last month in Behavioral Ecology and Sociobiology.”

bonus bonus: How to Dupe a Dung Beetle“A case of biological mimicry has been spotted in Ceratocaryum argenteum, a South African plant that tricks dung beetles into spreading its stinky seeds.”

bonus bonus bonus: Elephants: Large, Long-Living and Less Prone to Cancer“Dr. Schiffman and his colleagues found that elephants have evolved new copies of the p53 gene [“a gene that is crucial for preventing cancer”]. While humans have only one pair of p53 genes, the scientists identified 20 pairs in elephants.”

bonus bonus bonus bonus: DNA Sequenced for New Zealand’s First Dog – the kurī. woof!

bonus bonus bonus bonus bonus: Watch Drones Drop Thousands of Moths on Crops

bonus bonus bonus bonus bonus bonus: Honour, community and hierarchy in the feasts of the archery and crossbow guilds of Bruges, 1445–81

and the tweet of the week… (~_^)

(note: comments do not require an email. “Humans come then go, that is the way fate decreed on the Tablets of Destiny.”)


r.i.p. blank slate (and what does “the environment” mean anyway?)

so the mother of all meta-analyses of twin studies and the heritability of human traits was published the other day: “Meta-analysis of the heritability of human traits based on fifty years of twin studies” [pdf].

the authors looked at “17,804 traits from 2,748 publications including 14,558,903 partly dependent twin pairs, virtually all published twin studies of complex traits.” 14.5+ MILLION twin pairs! as james thompson said, this study pretty much represents “the mother of ‘F*** Off’ samples.” (~_^) in future, if someone says to you that twin studies were debunked a long time ago, blah, blah, blah, just point them to this paper.

and the upshot is: we are not blank slates. we never were.

from the paper, “[A]cross all traits the reported heritability is 49%.” in other words, these researchers found that pretty much half of the variance in all sorts of physical and behavioral traits in humans — the differences that we see between people — can be accounted for by genetics.

here’s a key table from the paper. i took the liberty of jiggling it around a bit so it would fit better on the blog (h2 is what you should be looking at here — that’s narrow sense heritabilty):

twin studies meta-analysis

the press has picked this up as there being an even split between nature and nurture, genes versus “the environment.” here, for example, from the huffington post*:

“Nature Or Nurture? The Long-Running Debate May Finally Be Settled”

“It’s an age-old debate: do our genes make us who we are, or is it the environment in which we were raised?

“There’s long been agreement that both ‘nature’ and ‘nurture’ play some role in determining many aspects of our physical and mental selves, from our height and weight to our intelligence and disposition. But as to which plays the bigger role in shaping us, scientists have never seemed to agree.

“That debate may now be over, thanks to a sweeping analysis of studies conducted around the world for more than five decades. The analysis — involving more than 14.5 million twin pairs from 39 countries — indicates that nature and nurture are virtually tied.

“Across all of our traits, in other words, genes and environment exert equal influence.”

yeeeessss…but what is “the environment”? on hearing that most people will think of things like reading bedtime stories to kids or playing mozart to your unborn fetus. but those sorts of things are decidedly not what the environment is in this context. from kevin mitchell of wiring the brain:

i’ve blogged this before, but i think we all need to read it again — from steven pinker on “the environment”:

“Even the technical sense of ‘environment’ used in quantitative behavioral genetics is perversely confusing. Now, there is nothing wrong with partitioning phenotypic variance into components that correlate with genetic variation (heritability) and with variation among families (‘shared environment’). The problem comes from the so-called ‘nonshared’ or ‘unique environmental influences.’ This consists of all the variance that is attributable neither to genetic nor familiar variation. In most studies, it’s calculated as 1 – (heritability + shared environment). Practically, you can think of it as the differences between identical twins who grow up in the same home. They share their genes, parents, older and younger siblings, home, school, peers, and neighborhood. So what could make them different? Under the assumption that behavior is a product of genes plus environment, it must be something in the environment of one that is not in the environment of the other.

But this category really should be called ‘miscellaneous/unknown,’ because it has nothing necessarily to do with any measurable aspect of the environment, such as one sibling getting the top bunk bed and the other the bottom, or a parent unpredictably favoring one child, or one sibling getting chased by a dog, coming down with a virus, or being favored by a teacher. These influences are purely conjectural, and studies looking for them have failed to find them. The alternative is that this component actually consists of the effects of chance – new mutations, quirky prenatal effects, noise in brain development, and events in life with unpredictable effects.

“Stochastic effects in development are increasingly being recognized by epidemiologists, frustrated by such recalcitrant phenomena such as nonagenarian pack-a-day smokers and identical twins discordant for schizophrenia, homosexuality, and disease outcomes. They are increasingly forced to acknowledge that God plays dice with our traits. Developmental biologists have come to similar conclusions. The bad habit of assuming that anything not classically genetic must be ‘environmental’ has blinkered behavioral geneticists (and those who interpret their findings) into the fool’s errand of looking for environmental effects for what may be randomness in developmental processes.”

and more from kevin mitchell:

“Just because some trait is not genetic does not mean it is not innate. If we are talking about how the brain gets wired, any number of prenatal environmental factors are known to have large effects. More interestingly, however, and probably a greater source of variance across the population, is intrinsic developmental variation. Wiring the brain is a highly complex procedure, reliant on cellular processes that are, in engineering terms, inherently ‘noisy’. Running the programme from the same starting point (a specific genotype) does not generate exactly the same output (the phenotype) every time. The effects of this noise are readily apparent at the anatomical level, when examining the impact of specific mutations, for example. In many cases, the phenotypic consequences are quite variable between genetically identical organisms, or even on two sides of the same brain. (If you want to see direct evidence of such developmental variation, take a directly face-on photograph of yourself, cut it in half and make mirror-image copies of the left and right sides. You will be amazed how different the two resultant faces are).

If the way the brain is wired is determined, not just by the starting genotype, but, to a large extent by chance events during development, then it is reasonable to expect this variation to be manifest in many psychological traits. Such traits may thus be far more innate than behavioural genetics studies alone would suggest.

in other words, it’s NOT genes + environment (or nature + nurture) — not as most people would think of it anyway. it’s genes + shared environment (which, since it’s shared, i.e. the same for the individuals in question, oughtn’t to make a difference, right?) + nonshared environment (which can include de novo mutations and development noise, which also may be heritable! iow, variation itself might be a genetic trait.). not much room for the effects of nurture here.

so, when you see a figure like 51% for “environmental” causes behind the differences we see in traits between people, remember that that very much includes biological causes like new mutations that are particular to individuals and developmental “noise,” which again may ultimately be regulated by genes.

(and, no, it’s not epigenetics either! see here and here and here.)

h/t once again to jayman for cluing me in on this in the first place! (^_^)

*to give credit where credit is due, the huff post journalist did mention that part of what’s included in “the environment” is measurement error. that is correct. edit: see comment below about measurement error. so the 49% heritabilty figure should be considered a very conservative figure.

p.s. – there’s even a dedicated website where you can have a look at all the heritability numbers for yourself. enjoy!

see also: Gone with the Wind from dr. james thompson, Nature, nurture and noise from kevin mitchell, and About Developmental Noise and Environmental Hereditarianism from jayman.

previously: it’s not nature and nurture…

(note: comments do not require an email. the blank slate.)

linkfest – 04/19/15

a linkfest! =D

Experimental evolution reveals hidden diversity in evolutionary pathways“Our findings show that parallel genetic evolution is strongly biased by constraints and we reveal the genetic bases. From such knowledge, and in instances where new phenotypes arise via gene activation, we suggest a set of principles: evolution proceeds firstly via pathways subject to negative regulation, then via promoter mutations and gene fusions, and finally via activation by intragenic gain-of-function mutations. These principles inform evolutionary forecasting and have relevance to interpreting the diverse array of mutations associated with clinically identical instances of disease in humans.”

Selectionism Strikes Back! – from razib.

Genomes carry a heavy burden“Most people’s DNA contains genetic mutations that are potentially lethal to offspring…. Most people carry one or two genetic mutations that can cause early death or infertility in their offspring….”

World’s oldest stone tools discovered in Kenya“Researchers…say they have found the oldest tools made by human ancestors — stone flakes dated to 3.3 million years ago. That’s 700,000 years older than the oldest-known tools to date, suggesting that our ancestors were crafting tools several hundred thousand years before our genus Homo arrived on the scene. If correct, the new evidence could confirm disputed claims for very early tool use, and it suggests that ancient australopithecines like the famed ‘Lucy’ may have fashioned stone tools, too.”

Neanderthals manipulated the bodies of adults and children shortly after death

Neandertal flutes debunked – @dienekes’.

IQ prediction from structural MRI – from steve hsu. see also: MRI-Based Intelligence Quotient (IQ) Estimation with Sparse Learning.

New brain science shows poor kids have smaller brains than affluent kids – see also: Credit, where credit is due, to Lyndsey Layton and Income, brain, race: Prof Kimberly Noble replies and Howitzer or Katyusha: Reply to Prof Noble at dr. james thompson’s blog. – and see also: In today’s social science, wishing makes it so – from charles murray.

Gene study may explain why some remain quick thinkers“Genetic differences could explain why some people are quicker thinkers in middle age and later life, a study of data from 30,000 people suggests.” – see also: GWAS for executive function and processing speed suggests involvement of the CADM2 gene.

Prediction of brain age suggests accelerated atrophy after traumatic brain injury – h/t stuart ritchie! who tweeted: “Super-cool new paper on how to predict someone’s age just from a brain image (r = .92!)”

National Wealth and IQ at the Edge: American Exceptionalism, East Asian Mediocrity – anatoly karlin’s “big-ass blog on national wealth, IQ, HBD, East Asians, smart fractions, etc.” (~_^)

In the beginning was the Word – dr. james thompson blogs on the recent woodley et al. paper “By their words ye shall know them: Evidence of genetic selection against general intelligence and concurrent environmental enrichment in vocabulary usage since the mid 19th century.”

Born That Way – from greg cochran.

Female Same-Sex Attraction Revisited – from jayman.

Examining the S factor in Mexican states – from emil kirkegaard.

Sex differences and vulnerability: how the male-female divide affects health“[S]ome studies have shown that premature baby girls will grow up to suffer greater language deficits than premature boys, whereas boys exposed to certain prenatal toxins will suffer greater deficits to spatial skills than girls similarly exposed, but because sex differences were never the original focus of the research no one, until Geary, has united these sex specific developmental problems and placed them in evolution’s bigger picture. Geary explains, ‘Sexually selected traits are the first to go; for example, low level exposure to prenatal toxins will affect play in boys but not their IQ: if you don’t measure the right thing you will fail to detect underlying problems.'” – h/t steve stewart williams!

Men up to five times more likely to commit sex crimes than the average male if they have brother or father convicted of a sex offence – h/t claire lehmann! who tweeted: “Survey of 21,566 men convicted of sex crimes from 1973- 2009 has revealed a strong genetic component to sex offending.” – see also: Sexual offending runs in families: A 37-year nationwide study.

Aggressive-Antisocial Boys Develop Into Physically Strong Young Men“We found that males’ antisocial tendencies temporally precede their physical formidability. Boys, but not girls, with greater antisocial tendencies in childhood attained larger increases in physical strength between the ages of 11 and 17. These results support sexual selection theory, indicating an adaptive congruence between male-typical behavioral dispositions and subsequent physical masculinization during puberty.”

Childhood Self-Control and Unemployment Throughout the Life Span: Evidence From Two British Cohort Studies“Analyzing unemployment data from two nationally representative British cohorts (N = 16,780), we found that low self-control in childhood was associated with the emergence and persistence of unemployment across four decades. On average, a 1-SD increase in self-control was associated with a reduction in the probability of unemployment of 1.4 percentage points after adjustment for intelligence, social class, and gender.”

Enlisting in the Military: The Influential Role of Genetic Factors“Given that enlistment in the U.S. military is completely voluntary, there has been a great deal of interest in identifying the various factors that might explain why some people join the military, whereas others do not. The current study expanded on this line of literature by estimating the extent to which genetic and environmental factors explained variance in the liability for lifetime participation in the military. Analysis of twin pairs drawn from the National Longitudinal Study of Adolescent to Adult Health (Add Health) revealed that 82% of the variance was the result of genetic factors, 18% of the variance was the result of nonshared environmental factors, and none of the variance was accounted for by shared environmental factors.” – from brian boutwell et al.

Risk of Suicide Among US Military Service Members Following Operation Enduring Freedom or Operation Iraqi Freedom Deployment and Separation From the US Military“Findings do not support an association between deployment and suicide mortality in this cohort. Early military separation (<4 years) and discharge that is not honorable were suicide risk factors.” – h/t michael story!

Verbal ability as a predictor of political preferences in the United States, 1974–2012“[H]igher vocabulary scores are associated with a greater likelihood that people place themselves on the ideological and political spectrum and that they vote in presidential elections, but have only small relationships with liberal-versus-conservative self-identification.”

Do our genes tell us how to vote? Study of twins says they might

On the Malleability and Plasticity of the History of the Blank Slate and 21st Century Moral Philosophy Advances Boldly into the 19th Century – from helian.

More on the younger Franz Boas – from peter frost.

Surnames and Y-Chromosomal Markers Reveal Low Relationships in Southern Spain – ruh roh.

New study finds genetic predisposition for noise-induced hearing loss

New function of obesity gene revealed

The placebome: Where genetics and the placebo effect meet

Chimps That Hunt Offer a New View on Evolution“[A] 10-year study of chimpanzees in Senegal shows females playing an unexpectedly big role in hunting and males, surprisingly, letting smaller and weaker hunters keep their prey. The results do not overturn the idea of dominant male hunters, said Jill D. Pruetz of Iowa State University, who led the study. But they may offer a new frame of reference on hunting, tools and human evolution. ‘We need to broaden our perspective,’ she said.”

Upper Palaeolithic ritualistic cannibalism at Gough’s Cave (Somerset, UK): The human remains from head to toe“Our present analysis of the postcrania has identified a far greater degree of human modification than recorded in earlier studies. We identify extensive evidence for defleshing, disarticulation, chewing, crushing of spongy bone, and the cracking of bones to extract marrow. The presence of human tooth marks on many of the postcranial bones provides incontrovertible evidence for cannibalism.”

Yes, You Can Catch Insanity“A controversial disease revives the debate about the immune system and mental illness.” – pediatric autoimmune neuropsychiatric disorders or “PANDAS”.

Hatfield and McCoy Feud — The Real Thing

Colors help set body’s internal clock“[Mice] use light’s changing color to set their own clocks, a finding that researchers expect will hold for humans, too.”

The Myth of the Angry Atheist“[T]hese results support the idea that people believe atheists are angry individuals, but they do not appear to be angrier than other individuals in reality.”

Flowers Are “Darker” at Lower Latitudes“UV radiation may explain why plants and animals closer to the equator come in darker varieties.”

The Disease That Turned Us Into Genetic-Information Junkies – brief history on tay–sachs disease research.

Antibiotic Resistant Bacteria Could Predate Antibiotics“A South American tribe, called the Yanomami, which was isolated for about 11,000 years prior to 2009, have gut bacteria that carry antibiotic resistance genes, according to new research. The Yanomami’s microbiome is far more diverse than that of Europeans or North Americans, but it also contains antibiotic resistant genes, despite never having had antibiotics. The findings suggest antibiotic resistance predates antibiotics, although it is possible the Yanomami ingested naturally occurring antibiotics in soil at some point.” – see also: The microbiome of uncontacted Amerindians.

Rotherham Worker ‘Told To Give Girls To Abusers’“The ex-protection worker says she repeatedly raised concerns about men taking girls away but her boss told her to ‘let them go’.” – also: State wards being groomed for prostitution by paedophile gangs“Organised gangs of paedophiles are grooming state wards as young as 12 for prostitution. Veteran child protection workers have told the Herald Sun they are powerless to protect the children in their care and that the sexual exploitation of state wards is ‘endemic’…. Victoria Police has set up a taskforce to investigate a gang of Afghani men in Dandenong suspected of preying on teens in care.” – australia now. =/

bonus: Jurassic Park in real life: The race to modify the DNA of endangered animals and resurrect extinct ones“Professor Church has applied a sophisticated and revolutionary ‘gene editing’ technique known as Crispr and has managed to get it working in elephant cells to carry out 14 precise changes to its genome. ‘We are now working on in vitro organogenesis [organ formation] and embryogenesis [embryo formation],’ he told The Independent in an email.”

bonus bonus: Genome Digest – findings from genomes of mountain gorilla, pseudomonas aeruginosa, canary, bird flu strain, and leprosy bacterium.

bonus bonus bonus: Through This Chemical Loop, Dogs Win Our Hearts

(note: comments do not require an email. woof?)