genetics
razib | May 15, 2009Rebecca Skloot has a piece up in Double X, Slate's new webzine, on the controversy around Myriad Genetics.
razib | May 14, 2009One of the peculiarities of American discussion about race is that skin color is assumed to be synonymous with racial distinctions. That is, skin color is not just a trait, but it is the trait which defines between population differences. There's a reason for this, the skin is the largest organ and it is very salient. Populations with little phylogenetic relationship to each other, from India to the Pacific to Southeast Asia have been referred to as "black" by lighter-skinned populations. No population is referred to by their neighbors as those "straight hairs," to my knowledge. But another…
razib | May 12, 2009Analysis of genomic diversity in Mexican Mestizo populations to develop genomic medicine in Mexico:
Mexico is developing the basis for genomic medicine to improve healthcare of its population. The extensive study of genetic diversity and linkage disequilibrium structure of different populations has made it possible to develop tagging and imputation strategies to comprehensively analyze common genetic variation in association studies of complex diseases. We assessed the benefit of a Mexican haplotype map to improve identification of genes related to common diseases in the Mexican population.…
clock | May 11, 2009Are you up to date on the hot debate in biology regarding how genes influence evolution? Some scientists contend genes are in the driver's seat. Others assign more pull to regulatory factors controlling genetic expression. At noon, Wednesday, May 27, come hear Duke biologist Greg Wray explore the importance of it all in a talk entitled "Hardware or Software: Searching for the Genetic Basis for Biological Diversity."
You may not want to miss this one. After Wray's talk, Pizza Talk embarks on its traditional three-month summer vacation. The next nine-month series debuts in September.
Sigma Xi…
grrlscientist | May 11, 2009tags: Blue House Sparrow, Passer domesticus, birds, blue feather color, plumage color, refraction
Blue-colored Male House Sparrow, Passer domesticus,
photographed in Sydney, Australia, April 2009.
Image: Richard Shears, Daily Mail [larger view].
Some of you might remember the remarkable photographs of the blue-colored male house sparrow, Passer domesticus, that was photographed in a garden in Sydney, Australia a couple weeks ago. I posted the images I had, along with my speculations, but was unable to go further than that. However, I tracked down the photographer and he has very kindly…
razib | May 11, 2009That seems the finding of this paper, Familial Aggregation of Survival and Late Female Reproduction:
Women giving birth at advanced reproductive ages in natural fertility conditions have been shown to have superior postmenopausal longevity. It is unknown whether improved survival is more likely among relatives of late-fertile women. This study compares survival past age 50 of men with and without a late-fertile sister in two populations: Utahns born in 1800-1869 identified from the Utah Population Database and Québec residents born in 1670-1750 identified from the Programme de recherche en…
razib | May 11, 2009Dienekes reports on an abstracts for paper presentations at the ESHG 2009. This was is particularly interesting:
European Lactase Persistence Allele is Associated With Increase in Body Mass Index
J. A. Kettunen et al.
The global prevalence of obesity, usually indexed by body mass index (BMI) cut-offs, has increased significantly in the recent decades, mainly due to positive energy balance. However, the impact of a selection for specific genes cannot be excluded. Here we have tested the association between BMI and one of the best known genetic variants showing strong selective pressure: the…
razib | May 10, 2009A few months ago I relayed preliminary data which suggested that Estonians are not like Finns. Now a new paper, Genetic Structure of Europeans: A View from the North-East:
Using principal component (PC) analysis, we studied the genetic constitution of 3,112 individuals from Europe as portrayed by more than 270,000 single nucleotide polymorphisms (SNPs) genotyped with the Illumina Infinium platform. In cohorts where the sample size was >100, one hundred randomly chosen samples were used for analysis to minimize the sample size effect, resulting in a total of 1,564 samples. This analysis…
edyong | May 9, 2009
Immunity to viral infections sounds like a good thing, but it can come at a price. Millions of years ago, we evolved resistance to a virus that plagued other primates. Today, that virus is extinct, but our resistance to it may be making us more vulnerable to the present threat of HIV.
Many extinct viruses are not completely gone. Some members of a group called retroviruses insinuated themselves into our DNA and became a part of our genetic code. Indeed, a large proportion of the genomes of all primates consists of the embedded remnants of ancient viruses. Looking at these remnants is like…
edyong | May 8, 2009The success of termites Âand other social insects hinges on their complex social systems, where workers sacrifice the ability to raise their own young in order to serve the colony and its queen - the only individual who reproduces. But this social order can be thrown into chaos by knocking out a single gene, and one that originally had a role in that other characteristic termite ability - eating wood.
Judith Korb from the University of Osnabrueck in Germany found that the queen termite relies on a gene called Neofem2 to rule over her subjects. Korb worked with the termite Cryptotermes…
razib | May 5, 2009In the comments below on the post on human population structure there was some request for a bigger global perspective. Below the fold I've placed a table with FST values which compare each population to the other. This an older population genetic statistic derived from the work of Sewall Wright, but you are almost certainly familiar with the talking point that "85% of variation is within races, and only 15% between." That is an FST insight. The higher the FST the greater the proportion of genetic variation which can be attributed to between population differences, so it serves as a rough…
razib | May 4, 2009In Nature, De novo establishment of wild-type song culture in the zebra finch:
Culture is typically viewed as consisting of traits inherited epigenetically, through social learning. However, cultural diversity has species-typical constraints, presumably of genetic origin... Zebra finch isolates, unexposed to singing males during development, produce song with characteristics that differ from the wild-type song found in laboratory11 or natural colonies. In tutoring lineages starting from isolate founders, we quantified alterations in song across tutoring generations in two social environments…
razib | May 3, 2009I still remember when L. L. Cavalli-Sforza's The History and Geography of Human Genes was a candle in the dark, illuminating human history with slivers of genetic data laboriously gathered and analyzed over decades. We've come a long way. Dienekes points me to a new paper, Fine-scaled human genetic structure revealed by SNP microarrays:
We report an analysis of more than 240,000 loci genotyped using the Affymetrix SNP microarray in 554 individuals from 27 worldwide populations in Africa, Asia, and Europe. To provide a more extensive and complete sampling of human genetic variation, we have…
razib | May 2, 2009David Brooks has a column out where he mulls over the role of time invested in amplifying talent:
If you wanted to picture how a typical genius might develop, you'd take a girl who possessed a slightly above average verbal ability. It wouldn't have to be a big talent, just enough so that she might gain some sense of distinction. Then you would want her to meet, say, a novelist, who coincidentally shared some similar biographical traits. Maybe the writer was from the same town, had the same ethnic background, or, shared the same birthday -- anything to create a sense of affinity.
...
The…
edyong | May 1, 2009For centuries, farmers have been genetically modifying their plants without even knowing it. That's the message from German scientists who found that grafting, a common technique used to fuse parts of two plants together, causes the two halves to swap genes with each other.
Grafting can involve fusing the stem of one plant (the scion) to the roots of another (the stock), or a dormant bud to another stem. There are many reasons for this - sometimes it's the most cost-effective way of cultivating the scion, sometimes the stock has properties that the scion lacks including hardiness or…
razib | April 30, 2009I've been fine tuning Ubuntu all day with goodies and getting drivers to work right, so I missed this paper on African genetics:
Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, 4 African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared…
razib | April 29, 2009Do you love or hate Cilantro?
K-T extinction debates: cranky "skeptics" or reasonable science?
Modularity and scalability
The elegant logic of dopamine
A Beacon from the Invisible Universe
razib | April 29, 2009Haplotypic Background of a Private Allele at High Frequency in the Americas:
Recently, the observation of a high-frequency private allele, the 9-repeat allele at microsatellite D9S1120, in all sampled Native American and Western Beringian populations has been interpreted as evidence that all modern Native Americans descend primarily from a single founding population. However, this inference assumed that all copies of the 9-repeat allele were identical by descent and that the geographic distribution of this allele had not been influenced by natural selection. To investigate whether these…
edyong | April 29, 2009HIV is an elusive adversary. The virus is so good at fooling the immune system that the quest for an HIV vaccine, or even a countermeasure to resist infections, has spanned two fruitless decades. But maybe a defence has been lurking in our genomes all this time.
Nitya Venkataraman from the University of Central Florida has managed to reawaken a guardian gene that has been lying dormant in our genomes for 7 million years. These genes, known as retrocyclins, protect monkeys from HIV-like viruses. The hope is that by rousing them from their slumber, they could do the same for us. The technique…
razib | April 28, 2009That's what Sandy at Digital Biology is suggesting from her analyses.... (also see Tara of Aetiology's response)