Crickets in two places fall silent to survive – “To hide themselves from deadly flies, crickets on two Hawaiian islands have evolved an inability to sing. Ten years ago, two years apart, males appeared on Kauai and Oahu with altered wings, which they would normally rub together to chirp and attract females. New findings published in the journal Current Biology show that the wing changes are physically different and arose from separate mutations. This makes the silent crickets a brand new example of ‘convergent evolution’.” – and some really rapid evolution!
Microbes May Drive Evolution of New Animal Species – “[S]ymbiosis — a long-term, stable and often beneficial interaction between organisms — could drive two populations apart, the first step in the development of new species. Although the idea has been floating around for nearly a century, it has only recently begun to gain traction in biology. This idea contrasts sharply with the traditional picture of evolution, in which new species emerge either from geological isolation or from a relentless struggle for food and mates. According to this new hypothesis, a host organism’s microbes might trigger changes in mating and reproduction that begin to define two different populations.” – h/t charles!
you gotta read this!: Coincidental Killers – “We assume that microbes evolved to attack humans when actually we are just civilian casualties in a much older war…. Many of the pathogens we fear most are mere tourists on the human body. Their real homes are oceans, caves, or soils. To understand them, we need to understand them within their natural ecology. Soil, for example, is an extreme habitat for a microbe: harsh and constantly changing. It can quickly oscillate from flood to drought, from scalding heat to freezing cold, and total darkness to intense solar radiation. It’s rife with other competing microbes, and crawling with hungry predators. We fear lions and tigers and bears; bacteria have to contend with phage viruses, nematode worms, and predatory amoebas. All of these conditions can lead to adaptations that make microbes accidentally suited for life in a human host. We are, after all, just another environment. A thick capsule that shields a microbe from dehydration could also shield it from our immune system. A spore that is adapted for travelling through the air can be easily inhaled into a respiratory tract.”
Genetically identical ants help unlock the secrets of larval fate – “A young animal’s genes are not the only genes that determine its fate. The genetic identity of its caretakers matters too…. [A] team led by Serafino Teseo of the University of Paris 13 used the unique aspects of the [clonal] ants’ biology to test the indirect role genes play in shaping the future identity of larvae and whole colonies by looking at the interaction between larvae and adults. They did so by observing the success of two ant clones, A and B, in pure colonies or mixed together into chimeric colonies. They also swapped broods, so A adults raised B larvae and vice versa. It turned out that A and B larvae developed differently depending on whether A or B nurses raised them. Left alone, pure A colonies produced the most young after six generations, making them more successful than B. However, in mixed colonies, B did better because its larvae more frequently turned into large adults that specialize in egg-laying rather than smaller, foraging-focused individuals….” – h/t rolf muertter!
Mitochondrial DNA of first Near Eastern farmers is sequenced for the first time – “According to conclusions, genetic affinities have been observed between the mitochondrial DNA of first Neolithic populations and the DNA of first Catalan and German farmers. This suggests that probably Neolithic expansion took place through pioneer migrations of small groups of population. Moreover, the two main migration routes — Mediterranean and European — might have been genetically linked. ‘The most significant conclusion — highlights Eva Fernández — is that the degree of genetic similarity between the populations of the Fertile Crescent and the ones of Cyprus an Crete supports the hypothesis that Neolithic spread in Europe took place through pioneer seafaring colonization, not through a land-mediated expansion through Anatolia, as it was thought until now….’ Other scientific studies had already provided signs of an alternative scenario of Neolithic spread in Europe different from the one through Anatolia. According to Turbón, ‘recent archaeological finds have proved that the Neolithic arrived to Cyprus around 10,600 years ago, some years after the first documentation of agricultural practices in the Near East.’ Architecture and burial models found in Cyprus’ sites are similar to the ones found in the Middle Euphrates basin, ‘that indicates a direct colonisation of these territories,’ highlights the author. ‘Besides, spatial interpolation of radiocarbon dates from different Neolithic sites in the Near East and Europe also suggests a first seafaring expansion through Cyprus,’ he concludes.” – orginal research article.
A twist in Austronesian origins – “The Taiwanese origin of Austronesians is widely accepted. A new preprint confirms this theory, but adds a new twist to the story of Austronesian dispersals, as it seems that in their western expansion, Austronesians picked up some Austroasiatic ancestry. This means either that Austroasiatic speakers preceded them in islands where Austronesian languages are now spoken, or that the Austronesians picked up this kind of ancestry in the mainland before settling in the islands.” – from dienekes.
A new allele for blond hair – “There is a widespread belief that whatever made Europeans fair-skinned also gave them their unique palette of hair and eye colors. In reality, fair skin has only a weak genetic linkage with either non-black hair or non-brown eyes.” – from peter frost. see also: A molecular basis for classic blond hair color in Europeans.
A Genetic Map of Fireworks in Time – “French Canadians and Slavs are both cases of populations which were once relatively modest and began in a narrow delimited region, but now are quite expansive and numerous. In the case of the East Slavs the demographic expansion also entailed the absorption of numerous Uralic tribes, as well as later Turks. And this illustrates one of the major details which I think has characterized the genetic turnover of human populations: phase shifts from a relatively static one defined by isolation by distance gene flow across clinal gradiants, to a rapid expansion of a small subset, and the overlay of this component as a palimpsest over the underlying variation. In some cases the replacement is nearly total, as in the modern United States. In other cases, as among Great Russians, the Slavic affinities of this population, and its association with Poles and other groups are clear, but there was a non-trivial uptake of exogenous segments which might allow for a reconstruction of the prior genetic landscape. These changes occur over short periods, and are bright fireworks against the comparatively static firmament.” – from razib.
Male faces ‘buttressed against punches’ by evolution – “A new theory suggests that our male ancestors evolved beefy facial features as a defence against fist fights. The bones most commonly broken in human punch-ups also gained the most strength in early “hominin” evolution. They are also the bones that show most divergence between males and females.” – h/t darwin evolution! – original research article.
Faster eye responses in Chinese people not down to culture – “New research from University of Liverpool scientists has cast doubt on the theory that neurological behaviour is a product of culture in people of Chinese origin. Scientists tested three groups – students from mainland China, British people with Chinese parents and white British people – to see how quickly their eyes reacted to dots appearing in the periphery of their vision…. The findings, published in the journal PLoS One, revealed that similar numbers of the British Chinese and mainland Chinese participants made high numbers express saccades, with the white British participants made far fewer. Culturally the British Chinese participants were similar to their white British counterparts and different to the mainland Chinese students.”
Cultural differences in human brain activity: A quantitative meta-analysis – “East Asians show enhanced activity underlying mentalizing and emotion regulation. Westerners show enhanced activity underlying self-reflection and emotional responses.”
Race could be a factor in head, neck cancer survival rates – “The national survival rates for African-Americans diagnosed with head and neck cancer have not improved in the last 40 years despite advances in the treatment and management of the disease, researchers have found. The researchers suggest that inherent genetic factors in African-Americans may make some tumors resistant to treatments.”
Severe intellectual disability diagnosed by analysis of entire genome – “[A]lmost all mental impairments are caused by new mutations that have not yet occurred in father or mother.” – h/t mr. robert ford!
New genes involved in food preferences will revolutionize diets and improve health – “The researchers undertook genome wide association studies (GWAS) to try to unravel the genetic basis for certain food preferences. 2311 Italian subjects participated in the discovery step, while 1755 from other European countries and from Central Asia were used in order to further verify the findings. They uncovered 17 independent genes related to liking for certain foods, including artichokes, bacon, coffee, chicory, dark chocolate, blue cheese, ice cream, liver, oil or butter on bread, orange juice, plain yoghurt, white wine and mushrooms. Surprisingly, none of the genes thus identified belonged to the category of taste or smell receptors…. In a second study, the researchers amassed the response of around 900 healthy adults from North Eastern Italy to salt, and related this to a DNA sequence variation found on the KCNA5 gene, known to be related to taste pathways in mammals.”
First direct evidence for human sex pheromones – “‘By using dynamic point-light displays that portray the gaits of walkers whose gender is digitally morphed from male to female, we show that smelling androstadienone systematically biases heterosexual females, but not males, toward perceiving the walkers as more masculine. By contrast, smelling estratetraenol systematically biases heterosexual males, but not females, toward perceiving the walkers as more feminine. Homosexual males exhibit a response pattern akin to that of heterosexual females, whereas bisexual or homosexual females fall in between heterosexual males and females. These effects are obtained despite that the olfactory stimuli are not explicitly discriminable. The results provide the first direct evidence that the two human steroids communicate opposite gender information that is differentially effective to the two sex groups based on their sexual orientation.'” – @deric bownds’ mindblog.
Genetic relatedness predicts contact frequencies with siblings, nieces and nephews: Results from the Generational Transmissions in Finland surveys – “Individuals have more contacts with full than with half siblings. Individuals have more contacts with nieces/nephews via full than via half siblings. Individuals have more contacts with nieces/nephews via sisters than via brothers.” – h/t jayman!
Beware Armchair Psychoanalysis – “‘Behavioral genetic studies have proved beyond a shadow of a doubt that heredity is responsible for a sizable portion of the variations in people’s personalities. Some people are more hot-tempered or outgoing or meticulous than others, and these variations are a function of the genes they were born with as well as the experiences they had after they were born. The exact proportion— how much is due to the genes, how much to the experiences—is not important; the point is that heredity cannot be ignored.'” – from jayman (quoting judith rich harris there).
SD-IE and other differentiation effects in Italy and Spain [pdf] – “SD–IE [strategic differentiation–integration effort] is a strategic differentiation effect present amongst indices of life history (LH), such that persons and populations of slow LH are more differentiated compared to those of fast LH. We found that this phenomenon is present amongst provinces in Italy and Spain, similarly to demonstrations among US states and Japanese prefectures. The average effect size of SD–IE was found to be bigger in Spain and Italy….. In the present study, we test SD–IE using regional-level data for counties in Spain and Italy.”
Is the smart fraction as valuable as previously thought? – “‘Consistent with the intellectual class theory advocated by Rindermann and Thompson (2011) and Rindermann et al. (2009), our research findings showed strong evidence that those people that have high IQ are the most relevant influence on economic development. Although our results suggested that all three examined IQ categories promote higher economic growth, the intellectual class has the highest impact followed by the mean ability and non-intellectual classifications. Similarly, the intellectual class also has a highly significant effect on generating technological progress, whereas the influence of the other two groups is immaterial.'” – @dr. james thompson’s blog.
The Biology of Risk – “The state of your body predicts your appetite for financial risk just as it predicts an athlete’s performance. If we understand how a person’s body influences risk taking, we can learn how to better manage risk takers. We can also recognize that mistakes governments have made have contributed to excessive risk taking.”
We can’t ignore the evidence: genes affect social mobility – “Why do so many people fail to accept the overwhelming evidence that genes contribute to academic achievement and thereby social status?” – h/t hbd bibliography!
Old chaps? 3,300-year-old trousers found in China may be world’s oldest – “Animal-fur menswear found on the bodies of two mummies in Xinjiang province ‘almost the same shape as today’s trousers'”
Grave find may be Western Europe’s earliest false tooth – “Archaeologists have identified what could be remains of the earliest false tooth found in Western Europe. The dental implant comes from the richly-furnished timber burial chamber of an Iron Age woman that was excavated in Le Chene, northern France.”
Cat People Are Smarter Than Dog People, New Study Shows – (~_^) – ftr, i like both. i’m not a speciesist!
bonus: Blind cavefish are able to ‘count’ – “Blind cave-dwelling fish are able to discriminate between different quantities, scientists say…. Researchers say it is the first time non-visual numerical abilities have been shown in fish.” – h/t mo costandi!
bonus bonus: Bees build mental maps to get home – “Study suggests the insects do not rely solely on the Sun as a compass…. ‘The surprise comes for many people that such a tiny little brain is able to form such a rich memory described as a cognitive map,’ says co-author Randolf Menzel, a neurobiologist at the Free University of Berlin.”
bonus bonus bonus: Nemo’s Dad Should Have Become His Mom, And Other Lies Children’s Movies Told You – h/t steve stewart williams!
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