genetics
razib | August 30, 2009Thomas Mailmund is going ape over chimps & humans again, Patterns of autosomal divergence between the human and chimpanzee genomes support an allopatric model of speciation. A review of a paper of the same name.
razib | August 30, 2009Anthropology.net points me to a new paper, Convergent genetic linkage and associations to language, speech and reading measures in families of probands with Specific Language Impairment:
We analyzed genetic linkage and association of measures of language, speech and reading phenotypes to candidate regions in a single set of families ascertained for SLI. Sib-pair and family-based analyses were carried out for candidate gene loci for Reading Disability (RD) on chromosomes 1p36, 3p12-q13, 6p22, and 15q21, and the speech-language candidate region on 7q31 in a sample of 322 participants…
razib | August 29, 2009Dienekes points me to a new paper, European Population Genetic Substructure: Further Definition of Ancestry Informative Markers for Distinguishing Among Diverse European Ethnic Groups. You've seen this song & dance before:
Population substructure in JapanPopulation substructure of Mexican MestizosEuropean population substructureGenetic Map of East AsiaThe genetics of Fenno-ScandinaviaFinns as European outliersUyghurs are hybridsGenetic structure of Eastern European populationsGenetic map of Europe; genes vary as a function of distance More genetic maps of EuropeHuman population structure…
edyong | August 28, 2009This article is reposted from the old Wordpress incarnation of Not Exactly Rocket Science.
Getting excited when fish produce sperm would usually get you strange looks. But for Tomoyuki Okutsu and colleagues at the Tokyo University of Marine Science and Technology, it's all part of a day's work. They are trying to use one species of fish as surrogate parents for another, a technique that could help to preserve species that are headed for extinction.
Okutsu works on salmonids, a group of fish that includes salmon and trout. Many members of this tasty clan have suffered greatly from over-…
razib | August 27, 2009So a friend of mine started IMing me about how crazy the John McWhorter & Michael Behe diavlog was on bloggingheads.tv. I was a bit surprised since there is no such diavlog, either on the bloggingheads.tv website, nor in their podcasts (which is where I usually am made to be aware of them). Well, here's the story:
John McWhorter feels, with regret, that this interview represents neither himself, Professor Behe, nor Bloggingheads usefully, takes full responsibility for same, and has asked that it be taken down from the site. He apologizes to all who found its airing objectionable.…
razib | August 26, 2009There's a new National Geographic special out, The Human Family Tree, which readers might be interested in. Next showing is on the 30th. Seems to be an extension of The Genographic Project.
Clips below the fold:
gregladen | August 25, 2009Natural Selection is the key creative force in evolution. Natural selection, together with specific histories of populations (species) and adaptations, is responsible for the design of organisms. Most people have some idea of what Natural Selection is. However, it is easy to make conceptual errors when thinking about this important force of nature. One way to improve how we think about a concept like this is to carefully exam its formal definition.
In this post, we will do the following:
Discuss historical and contextual aspects of the term "Natural Selection" in order to make clear…
razib | August 25, 2009Speaking of Richard Dawkins, he's back to science, in this case an excerpt from his new book, The Greatest Show on Earth: The Evidence for Evolution:
The evolution of the dog, then, if Coppinger is right, was not just a matter of artificial selection, but a complicated mixture of natural selection (which predominated in the early stages of domestication) and artificial selection (which came to the fore more recently). The transition would have been seamless, which again goes to emphasise the similarity -- as Darwin recognised -- between artificial and natural selection.
Nothing new in the…
razib | August 24, 2009Dienekes points to a new paper, Amerindian mitochondrial DNA haplogroups predominate in the population of Argentina: towards a first nationwide forensic mitochondrial DNA sequence database:
The study presents South American mitochondrial DNA (mtDNA) data from selected north (N = 98), central (N = 193) and south (N = 47) Argentinean populations. Sequence analysis of the complete mtDNA control region (CR, 16024-576) resulted in 288 unique haplotypes ignoring C-insertions around positions 16193, 309, and 573; the additional analysis of coding region single nucleotide polymorphisms enabled a fine…
razib | August 24, 2009
A month ago Larry Moran made reference to Fern Elsdon Baker's new book, The Selfish Genius: How Richard Dawkins Rewrote Darwin's Legacy. Moran was a bit disappointed by the previews, his pet hobby-horse being the revolutionary impact of the neutral theory of molecular evolution, while Elsdon-Baker seems rather fixated on the potential of Neo-Lamarckism, especially epigenetics. Well, I've read the book, and Larry Moran would probably be disappointed, though she mentions Stephen Jay Gould and pluralism a bit, there's really very little engagement with the 20th century debates in evolutionary…
gregladen | August 21, 2009In my initial list of Falsehoods, I included these two closely related items:
Evolution has stopped for humans; and
Serious scientists often entertain the question: "Has evolution stopped for humans?"
I'll make the distinction between them clear eventually. For now, let's focus on the first: Has evolution stopped for humans or not?
The reason we bring up these falsehoods to begin with is because examining them exposes assumptions or requires the investigation of knowledge that is worth talking about. In this case, the deeper question is this: What is evolution exactly? So, this is a…
razib | August 20, 2009
Common body mass index-associated variants confer risk of extreme obesity:
To investigate the genetic architecture of severe obesity, we performed a genome-wide association study of 775 cases and 3197 unascertained controls at 550 000 markers across the autosomal genome. We found convincing association to the previously described locus including the FTO gene. We also found evidence of association at a further six of 12 other loci previously reported to influence body mass index (BMI) in the general population and one of three associations to severe childhood and adult obesity and that cases…
nisbetmc | August 18, 2009I have long argued that Francis Collins would make a strong candidate to head the NIH, considering his scientific credentials, his past administrative experience, and his ability to communicate effectively. Unlike some critics, I see his work on the relationship between science and religion as a major bonus, offering an important middle ground voice on the topic.
Yet an opinion article appearing this week at The Scientist offers a valuable constructive critique: Collins, like many others in science, may be guilty at times of hyping and over-selling the promise of research. The general…
razib | August 17, 2009Below I repeated the contention that while schizophrenia is a genuine biologically rooted behavioral disease which can not be cured through will, many forms of addiction are not. That is why the genetics of schizophrenia are of such great interest, if the biological pathways of the pathology can be elucidated presumably a cure may be found. Unfortunately finding the genes is easier said than done, see Schizophrenia: The Mystery of the Missing Genes.
razib | August 16, 2009A very thorough paper in PLoS Genetics on the "obesity gene," FTO, A Mouse Model for the Metabolic Effects of the Human Fat Mass and Obesity Associated FTO Gene:
Geneticists have identified many gene regions that cause human disease by using multiple genetic markers in large populations to find gene regions associated with disease. However, it is often not clear precisely which gene in any given region causes the disease or how the gene exerts its functional effect. For example, a gene variant in the non-coding region of FTO enhances obesity risk, but it is not clear if this is an effect of…
razib | August 14, 2009p-ter reports on a fascinating new paper, The Transcriptional Repressor DEC2 Regulates Sleep Length in Mammals:
Sleep deprivation can impair human health and performance. Habitual total sleep time and homeostatic sleep response to sleep deprivation are quantitative traits in humans. Genetic loci for these traits have been identified in model organisms, but none of these potential animal models have a corresponding human genotype and phenotype. We have identified a mutation in a transcriptional repressor (hDEC2-P385R) that is associated with a human short sleep phenotype. Activity profiles and…
razib | August 13, 2009Taking a much needed break from vocational productivity, Dan MacArthur of Genetic Future has been on something of a blogging tear this week. Check out his emergence from hibernation.
razib | August 11, 2009Dan MacArthur has the details. What, no bailout from the government of Iceland?
ejohnson | August 5, 2009
A recent post by Megan McArdle on her Atlantic blog about the heritability of obesity prompted a discussion on ScienceBlogs about the often confused meaning of heritability. As Razib explains on Gene Expression, "Heritability is the proportion of trait variance within the population explainable by variance of genes." The more an environment is able to effect differences between individual expressions of a trait in a single population, the lower the heritability of that trait. In the case of the US obesity epidemic, generational differences in obesity levels do not mean that obesity is not…
razib | August 4, 2009Dienekes points me to a new paper, Demographic history of Canary Islands male gene-pool: replacement of native lineages by European (PDF). Here are the results:
Autochthonous (E-M81) and prominent (E-M78 and J-M267) Berber Y-chromosome lineages were detected in the indigenous remains, confirming a North West African origin for their ancestors which confirms previous mitochondrial DNA results. However, in contrast with their female lineages, which have survived in the present-day population since the conquest with only a moderate decline, the male indigenous lineages have dropped constantly…