genetics
razib | March 31, 2009Dan MacArthur has a post up where he discusses 23andMe's outreach to "mommy bloggers." This makes economic sense for any firm in this field. There's only so much money to be made out of telling blue eyed nerds that they carry the gene for blue eyes. To use a computer analogy the way you can get the Apple II of personal genomics would be to convince millions of pregnant women of the utility of your tools.
razib | March 30, 2009In the wake of last week's paper, looks like another one is coming down the pipe, Hundreds of Natural-Selection Studies Could be Wrong, Study Demonstrates:
"These statistical methods have led many scientists to believe that natural selection acted on many more genes in humans than it did in chimpanzees, and they conclude that this is the reason why humans have developed large brains and other morphological differences," said Nei. "But I believe that these scientists are wrong. The number of genes that have undergone selection should be nearly the same in humans and chimps. The differences…
razib | March 30, 2009A few years ago a paper came out, How Well Does Paternity Confidence Match Actual Paternity?:
Evolutionary theory predicts that males will provide less parental investment for putative offspring who are unlikely to be their actual offspring. Crossâculturally, paternity confidence (a man's assessment of the likelihood that he is the father of a putative child) is positively associated with men's involvement with children and with investment or inheritance from paternal kin. A survey of 67 studies reporting nonpaternity suggests that for men with high paternity confidence rates of nonpaternity…
razib | March 30, 2009The paper is pretty straightforward, Copy number variation in African Americans:
Employing a SNP platform with greater than 500,000 SNPs, a first-generation CNV map of the African American genome was generated using DNA from 385 healthy African American individuals, and compared to a sample of 435 healthy White individuals. A total of 1362 CNVs were identified within African Americans, which included two CNV regions that were significantly different in frequency between African Americans and Whites (17q21 and 15q11). In addition, a duplication was identified in 74% of DNAs derived from cell…
razib | March 27, 2009A few days ago The New York Times had a blog post up which addressed the relationship between genes & environment in shaping our behavior & choices (see Genetic Future). One of the authors even posted a follow up comment where they evinced some surprise at the bile of the responses. I have to say that some people are naive; statistical sciences are a good reflection of the tenor of society. If you say a trait is 50% heritable, that is a statement of fact, but individuals will "spin it" however they want to based on their own outlook and the preferences of their target audience. Years…
razib | March 25, 2009Dan MacArthur already posted some of the supplementary figures from Signals of recent positive selection in a worldwide sample of human populations, but he didn't put up one that I thought was really striking. The text:
First, there is extensive sharing of extreme iHS and XP-EHH signals between Europe, the Middle East, and Central Asia, while overlap between other regions is much more limited. In fact, 44% of the genomic segments in the 1% tail of iHS in Europe fall in the 5% tail for both the Middle East and Central Asia (89% are shared between Europe and at least one of these two), while…
razib | March 25, 2009Nick Wade in The New York Times has a piece on a review on the relationships between male competition, signaling and sexual selection. If the topic interests you I strongly recommend Animal Signals, John Maynard Smith's last book.
amillikan | March 25, 2009A new paper published in Genome Research provides the most comprehensive scan to date of the genetic signatures of natural selection resulting from the last 10-40,000 years of human evolution, with some intriguing results. The results show strikingly different patterns of selection in distantly related human populations, suggesting that different human groups have adapted to their environments in different ways. Many of the regions seen to be most subject to selection contain genes of unknown function—or no genes at all—but regions linked to increased risk of type 2 diabetes showed a…
razib | March 24, 2009Genetic Future's summary of Signals of recent positive selection in a worldwide sample of human populations is an excellent complement to mine. Highly recommended.
sporte | March 24, 2009For the past few months, the shake-up that began with Next Generation DNA Sequencing has been forcing me to adjust to a whole new view of things going on inside of a cell. We've been learning things these past two years that are completely changing our understanding of the genome and how it works and it's clear we're never going back to the simple view we had before.
What's changed? The two most striking changes, to me at least, are the new views of the way the genome is put together and what the cell does with the information.
They just don't assemble chromosomes like they used to.
I used to…
edyong | March 24, 2009Be it in sports or comedy, they say that timing is everything. In evolution, it's no different. Many of the innovations that have separated us from other apes may have arisen not through creating new genetic material, but by subtly shifting how the existing lot is used.
Take our brains, for example. In the brains of humans, chimps and many other mammals, the genes that are switched on in the brain change dramatically in the first few years of life. But Mehmet Somel from the Max Planck Institute for Evolutionary Anthropology has found that a small but select squad of genes, involved in the…
razib | March 24, 2009John Hawks & Daniel MacArthur have already pointed to a new paper in Genome Research, Signals of recent positive selection in a worldwide sample of human populations. As Dan notes, it's Open Access, so you can read the PDF yourself. That being said, "Just read it!" might be somewhat a tall order if you don't have some background, so make sure to read the papers at this link. In particular the paper refers to two tests for detecting natural selection which utilize haplotype structure, integrated haplotype score (iHS) and cross population extended haplotype homozygosity (XP-EHH).
One of…
razib | March 23, 2009I thought this Genetic Future post was an exaggeration, as it seemed to indicate that the Gene Sherpa was accusing 23andMe of terrorism. I thought there has to be context, right? Uh, not really:
In healthcare, imagine if your doctor was found to be breaking the law. Stole from Medicare? Non-Compliance with State regulations? Spousal Abuse? Selling Drugs?
Most of these are career killers. In fact in CT we just had a large group of GI doctors who are now not doing so well because one of their partners was just charged with endangering a minor.
Why is it so vital that physicians, nurses and…
razib | March 23, 2009
Richard Sturm in Human Molecular Genetics has a really good review of the current state of pigmentation genetics, with a human centric focus:
The genetic basis underlying normal variation in the pigmentary traits of skin, hair and eye colour has been the subject of intense research directed at understanding the diversity seen both between and within human populations. A combination of approaches have been used including comparative genomics of candidate genes and the identification of regions of the human genome under positive selection, together with genome-wide and specific allele…
edyong | March 23, 2009Sixty-five million years ago, life on Earth was sorely tested. One or more catastrophic events including a massive asteroid strike and increased volcanic activity, created wildfires on a global scale and dust clouds that cut the planet's surface off from the sun's vital light. The majority of animal species went extinct including, most famously, the dinosaurs. The fate of the planet's plants is less familiar, but 60% of those also perished. What separated the survivors from the deceased? How did some species cross this so-called "K/T boundary"?
Jeffrey Fawcett form the Flanders Institute for…
grrlscientist | March 22, 2009tags: evolutionary biology, mate choice, sex determination, genetic compatibility, behavioral ecology, Gouldian Finch, Erythrura gouldiae, peer-reviewed paper
The three color morphs of Gouldian finches, Erythrura gouldiae.
Image: Sarah Pryke, Macquarie University.
Gouldian finches, Erythrura gouldiae, are small cavity-nesting passerines that are endemic to open savannahs adjacent to mangrove swamps in northern Australia. These finches eat a variety of native grass seeds, but to meet the increased energetic and nutritional demands of rearing chicks, they primarily eat insects when…
sporte | March 22, 2009What do the missing Romanov children, genetically engineered humans, financial risk taking, and poop have in common?
You can read about all these topics from this month's Gene Genie carnival at Mary Meets Dolly.
Who would have thought that mutations could be so much fun?
razib | March 21, 2009A few years ago a brown friend of mine complained that there were all these diseases which non-white people were susceptible to at a higher rate (e.g., Type II Diabetes, hypertension, ateriosclerosis, etc.), perhaps the white race was really superior (or medical geneticists were entering into a conspiracy to prove that this was so). So with that, I point to a new PLoS Genetics paper, An African Ancestry-Specific Allele of CTLA4 Confers Protection against Rheumatoid Arthritis in African Americans:
Rheumatoid arthritis (RA) is a systemic autoimmune condition affecting the synovial membranes of…
razib | March 21, 2009Genetic Future has a post which mulls over the idea that not screening for particular diseases is similar to child abuse. I was interested in this last comment:
Naturally there are objections to embryo screening among religious conservatives who believe that inflicting severe disease on children is the will of God - but why does the prospect raise such unease among even the secular community? I share Le Page's puzzlement on this question, and would invite opponents to lay out any well-reasoned arguments against routine screening in the comments below.
Religious conservatives, particularly…
razib | March 15, 2009Genetic Future points to a new paper which suggests that inbreeding is declining over time. Their methodology involved surveying different age cohorts and noting the decreased levels of homozygosity among the youth. Dienekes points out that the use of living people might simply be confounding inferred mating patterns with the fact that homozygous individuals have a higher life expectancy. The plausibility of these two hypotheses varies based on how much weight you put on the shifting of mating patterns. In Consanguinity, Inbreeding, and Genetic Drift in Italy the authors used Catholic…