genetics
razib | March 15, 2009Dienekes & John Hawks have already blogged a new paper, Geographical structure and differential natural selection amongst North European populations:
Population structure can provide novel insight into the human past and recognizing and correcting for such stratification is a practical concern in gene mapping by many association methodologies. We investigate these patterns, primarily through principal component (PC) analysis of whole genome SNP polymorphism, in 2099 individuals from populations of Northern European origin (Ireland, UK, Netherlands, Denmark, Sweden, Finland, Australia and…
razib | March 12, 2009Like the little boy who can't help sticking his finger into the socket, Dan MacArthur is talking about race, IQ & genetics again. He quotes an exchange in nature where a researcher states:
So, given that we have logical reason to hypothesize about differences in cognitive abilities, why would we expect to measure these by using a single number such as IQ, which suggests there must be a hierarchy of cognitive function? The prediction surely is that each population will adapt to be better at the particular cognitive tasks that are most important for survival in its own environment. If this…
razib | March 11, 2009
p-ter has a post up which he illustrates with a photograph of a rather ghoulish prosimian. I've read that some of the Victorians found chimpanzees & gorillas almost obscene because of their simultaneous resemblance to humanity and manifest inhumanity. I somewhat feel the same about prosimians, especially tarsiers. No doubt this is due to my relative familiarity with immature chimpanzees on television shows. In any case, there is a new paper out which demonstrates that the genetic architecture of blue eyes in two species of lemurs is not similar to that in humans. Contrast this to…
mikethemadbiologist | March 11, 2009A while ago, economist Paul Krugman described the institutional loss of knowledge in the discipline of economics:
And the latter group, the equilibrium macro side, was so convinced of the logical correctness of its position that schools dominated by that view stopped teaching demand-side economics. (Schools dominated by new Keynesians, on the other hand, did teach real business cycle theory.) I haven't been able to dig up the quote, but somewhere along the line Ed Prescott declared that his students wondered who Keynes was, because he was never mentioned in their courses.
And those trained…
clock | March 11, 2009From Sigma Xi:
NCSU molecular biologist Jorge Piedrahita has cloned pigs and explored why they are not carbon copies despite sharing the same DNA. Now he is trying to crack puzzles that could result in transgenic animals useful in human and veterinary medicine. His studies in cloned pigs led him to an unusual family of genes called imprinted genes, involved in placental function and fetal development. Recently he found they are implicated in human diseases too and is developing stem cell technologies in swine to try to speed up clinical applications in people.
To learn more, come hear…
gregladen | March 10, 2009I first became acquainted with the Romanovs (as historical figures, not the actual Romanovs) reading in middle school about Russian History. Later, someone turned me on to Massie's Nicholas and Alexandra, which is quite a well known popular historical account of the last Czar of Russia and his family. Everyone knows the story of the end. The core of Czar's family -- the Czar Nicholas, his wife Alexandra, and his children -- had been arrested and all of them were transported to a remote location in the Urals. A complex series of events had begun involving Czarist and Revolutionary forces…
razib | March 10, 2009At Genetic Future. As noted by Dr. MacArthur this is currently an exception to the rule when it comes to predicting traits from genes. This can come in handy when you have DNA samples from a crime scene and reconstructing the appearance of the perp.
Related: OCA2, the "blue eye gene".
amillikan | March 10, 2009Among the non-coding DNA that composes a large percentage of the genomes of humans and other eukaryotic organisms, pseudogenes are genes that were once active but were rendered defunct by mutations at some point in evolutionary history. But some pseudogenes may regain their functionality. A study published in PLoS Genetics last week revealed that a gene that codes for a member of the immunity-related GTPase protein family, IRGM, was subject to a frameshift mutation in an ancestor of primates 40 million years ago, due to insertion of a small fragment of DNA. The non-functional pseudogene…
ddobbs | March 10, 2009Evolutionary Novelties ponders placentas:
For me one of the most visceral confirmations of the common descent of humans and other mammals came while witnessing the birth of my children. Having grown up on a small farm, I have vivid memories of the birth of kittens, lambs, and goats; and after the births of my children, I was struck by the similarity of human placenta and umbilical cord to those of other mammals. Given common descent, how did something as complex as the mammalian placenta originate in the first place? The answer, according to research published last summer in Genome Research…
razib | March 9, 2009Advanced Paternal Age Is Associated with Impaired Neurocognitive Outcomes during Infancy and Childhood:
A sample of singleton children (n = 33,437) was drawn from the US Collaborative Perinatal Project. The outcome measures were assessed at 8 mo, 4 y, and 7 y (Bayley scales, Stanford Binet Intelligence Scale, Graham-Ernhart Block Sort Test, Wechsler Intelligence Scale for Children, Wide Range Achievement Test). The main analyses examined the relationship between neurocognitive measures and paternal or maternal age when adjusted for potential confounding factors. Advanced paternal age showed…
gregladen | March 9, 2009Why is there "junk DNA"? What is Junk DNA? What is a Pseudogene? What is Gene Duplication?
Goodness, you certainly do have a lot of questions. And some of them can be answered, or at least addressed, on examination of a very interesting new paper recently published about a gene that became a useless "pseudogene" a very long time ago and has recently been revived by evolution to serve once again as an active member of the community we know of as the genome. In humans.
"Junk DNA" is mainly DNA that is not used in the day to day course of coding for various products such as proteins…
razib | March 8, 2009Evolution is a fact. Lineages change over time, and respond to selection pressures as well as being buffeted by stochastic processes. The arguments about the particular details of the process of evolution can be very vociferous. Scientists are human too, and great evolutionary biologists such as R. A. Fisher stooped to venomous insult when backed into a corner (see his disputes with Sewall Wright during the 1930s). But the superstructure of human foibles and follies rests upon a foundation of genuine scientific dispute, and attempts to refine models which map onto reality.
For example…
gregladen | March 7, 2009I recently posted about the work by Pagel and colleagues regarding ancient lexicons. That work, recently revived in the press for whatever reasons such things happen, is the same project reported a while back in Nature. And, as I recall, I read that paper and promised to blog about it but did not get to it. Yet.
So here we go.
The tail does not wag the dog
The primary finding of the Pagel et al. study is this: When comparing lexicons from different languages, meanings that shared a common word in an ancestral language change over time more slowly if the word in question is used more…
clock | March 7, 2009From SCONC:
Tuesday, March 24
6:30-8:30 pm
Science Cafe, Raleigh: Gene-Environment Interactions
EPA statistician and geneticist David Reif discusses the interplay between our genes and the environment. What does our shared evolutionary history have to do with common, complex diseases? How might genetics shape differential susceptibility to the multitude of chemicals--both manufactured and natural--present in the environment? How do modern lifestyles impact the evolutionary process? Tir Na Nog, 218 South Blount Street, Raleigh, NC, 919.833.7795
RSVP to katey.ahmann@ncmail.net
razib | March 6, 2009Genetic Determinants of Height Growth Assessed Longitudinally from Infancy to Adulthood in the Northern Finland Birth Cohort 1966. Here's the important part from the discussion:
To summarise, our results show that nearly half of the genetic variants associated with adult height in this sample had a measurable effect on PHV [peak height velocity] in infancy or puberty. Only one variant was associated with PHV in both infancy and puberty. We found suggestive evidence that the associations of some of the variants may be age-dependent. The majority of signals associated with growth parameters in…
awild | March 5, 2009This photo was ultimately rejected for a journal cover (it was the wrong shape!) but I shot it to accompany a research article that used museum specimens of midwestern bumblebees to compare current levels of genetic diversity with previous decades. Since this image won't appear in print anytime soon, I thought I'd share it here instead.
photo details: Canon 35mm f2.0 prime lens on a Canon EOS 20D
ISO 200, 1/125 sec, f/5, indirect strobe
edyong | March 5, 2009The world of genetics is filled with stories that are as gripping as the plot of any thriller. Take the IRGM gene - its saga, played out over millions of years, has all the makings of a classic drama. Act One: setting the scene. By duplicating and diverging, this gene thrived in the cells of most mammals as a trinity of related versions that played vital roles in the immune system.
Act Two: tragedy strikes. About 50 million years ago, in the ancestors of today's apes and monkeys, the entire IRGM cluster was practically deleted, leaving behind a sole survivor. Things took a turn for the worse…
razib | March 5, 2009Dienekes comments on the paper which showed genetic substructure among a set of Sardinian villages:
The take-home lesson is that wherever gene flow is impeded, no matter how geographically close, population differentiation can be recovered with dense autosomal genotype data.
Really fine-scale ancestry analysis is now possible; I suspect that a combination of geography, religion, social class, language, and ethnic identification will be found to be predictive of a person's broad genetic makeup and vice versa. But, to discover these correlations, a large-scale collection of genotypic data is…
razib | March 5, 2009FuturePundit has some musings on the possiblities of $100 genome sequencing in 5 years:
Cheap portable DNA sequencers will also lead to surreptitious DNA sequencing of people without their awareness. I expect to see this on the dating and bar scene. I also expect to see it in job interview and business negotiation situations. Check to see if your potential employee or business partner has genes that give them cognitive traits to avoid or embrace.
To be frank, this seems to b aiming too low. After all, why look to genetic profiles which suggest potentialities or probabilities? If you can get…
razib | March 4, 2009Geographical Affinities of the HapMap Samples:
The CHB and JPT are readily distinguished from one another with both autosomal and Y-chromosomal markers, and results obtained after combining them into a single sample should be interpreted with caution. The CEU are better described as being of Western European ancestry than of Northern European ancestry as often reported. Both the CHB and CEU show subtle but detectable signs of admixture. Thus the YRI and JPT samples are well-suited to standard population-genetic studies, but the CHB and CEU less so.