genetics
gregladen | January 3, 2008Daily alcohol use by males has been shown to increase sexual arousal and decrease sexual inhibition.
In Fruit Flies.
The current (Jan 2) issue of PLoS ONE includes a paper by Lee et al exploring thye physiological side of changes in sexual behavior under the influence of alcohol, with an eye towards understanding this process in humans, using an animal model.
Alcohol has a strong causal relationship with sexual arousal and disinhibited sexual behavior in humans; however, the physiological support for this notion is largely lacking and thus a suitable animal model to address this issue is…
razib | December 31, 2007Looking for Nm* values for humans I stumbled across an interesting paper, Estimating sex-specific processes in human populations: Are XY-homologous markers an effective tool?:
...To test this idea, we analyzed XY-homologous microsatellite diversity in 33 human populations from Africa, Asia and Europe. Interpopulation comparisons suggest that the generally discordant pattern of genetic variation observed for X- and Y-linked markers could be an outcome of sex-specific migration processes (mfemales/mmales ~ 3) or sex-specific demographic processes (Nfemales/Nmales ~ 11) or a combination of both…
clock | December 29, 2007Two grape genomes were published this year, one in Nature, the other in PLoS ONE. Larry Moran explains the methodologies and results of both and discusses the trustworthiness of each. The Nature paper is explained in The Grapevine Genome, and the PLoS ONE paper is discussed in The Second Grapevine Genome Is Published. Obligatory Readings of the Day.
pharyngula | December 28, 2007Next time I'm told by some "scientific" racist that he has evidence backing up his contention that certain races are inferior, I'm just going to tell him that there is one more experiment he has to do.
grrlscientist | December 27, 2007tags: researchblogging.org, champion racehorses, thoroughbred, genetic correlation, heritability, Equus caballus, nature versus nurture
Seattle Slew (1974-2002), the only undefeated horse to win the Triple Crown (1977).
I have been thinking about a paper that was published last week, that analyzed the effects of "nature versus nurture" on the development of a champion racehorse. In short, this paper found that the effects of a horse's pedigree is minor when compared to its environment .. the combined effects of training, diet, choice of races entered, jockey skill and of course, injuries…
razib | December 27, 2007Genome Wide Association (GWA) Study for Early Onset Extreme Obesity Supports the Role of Fat Mass and Obesity Associated Gene (FTO) Variants. Even if this is true, these correlations between particular alleles and obesity hold for the modern German lifestyle. I guarantee you that population level diversity in weight correcting for height was sharply attenuated when all Germans were basically farmers and laborers. It seems possible to me that in pre-modern times "obesity alleles" might have been selected for something different in an environment where gaining a lot of weight and becoming…
razib | December 23, 2007Hometown Reacts: Residents Respond To Pregnancy News in relation to Jamie Lynn Spears & Casey Aldridge's impending parenthood:
But we did manage to talk to a few locals, who, quite honestly, weren't too shocked to learn that Britney's little sister was pregnant, either because teen pregnancies aren't all that uncommon in Kentwood, or because, after all, she is Britney's little sister.
"They tried to keep it secret, I don't know why. In Kentwood, everything gets out. You got kids who are 13 or 14 and pregnant in Kentwood, we're about used to it around here," Donald Church said. "But it…
gregladen | December 22, 2007Gene Expression has the second in a pair of posts on race that is worth a close look. In Why phenotypic races may not disappear, G.E. speaks of the particulate nature of inheritance in relation to culturally defined racial types (that are in turn based on appearance).
There is the idea in the minds of some that interracial relations in the most intimate sense will banish racism or racial consciousness. To me that seems unlikely, though Latin American nations do not exhibit the sort of racism based on ancestry traditional in the United States, they do retain a marked preference for those…
razib | December 21, 2007Specifically, as evolgen points out the acceleration paper was focused on adaptive evolution, the subset of allele frequency changes driven predominantly by the force of natural selection. What's the rest? Read the post.
Why does this matter? Evolution is a science, and in science this sort of pedantic precision in definition, terminology and meaning matters a great deal because it is embedded in a contingent system. One of the most frustrating things about the necessity of the rearguard action against Creationists is that the "controversy" swamps this reality, that evolution is a science…
gregladen | December 21, 2007A multilocus model with a dominant gene for magic might exist, controlled epistatically by one or more loci, possibly recessive in nature. Magical enhancers regulating gene expressionmay be involved, combined with mutations at specific genes implicated in speech and hair colour such as FOXP2 and MCR1.
The most important thing about this study is not its conclusion, but what we will do with it.
The study, in the current issue of the British Medical Journal (here), is surely to be picked up by some of the major news agencies. Another recent study, linking testosterone to humor, was, ans passed…
razib | December 20, 2007In response to my post Mixed-race but homogeneous appearance? several individuals mooted the possibility that admixture may result in the vanishing of race as a social construct. Actually, I don't think this is the true. To the left is a photo from my post Can you tell if you're black or white? where I explored the genetics of a case where two black-white biracial parents produced fraternal twin daughters of disparate appearance. While one sister seemed to favor her African ancestors in look, another sister seemed to resemble her European forebears. Across the full sample space of their…
gregladen | December 19, 2007African American children may have reduced verbal ability compared to other children to a degree that is roughly equivalent to missing a year in school, according to a recently published paper. Is this evidence of a racial difference?
The study by Sampson et.al., published in the Proceedings of the National Academy of Sciences included more than 200 children aged 6-12 living in Chicago, and followed these children over seven years. The study controlled for poverty, and interestingly, poverty was not found to be a good predictor of differences in verbal ability.
The researchers consider…
razib | December 19, 2007So The Superficial is reporting that Jamie Lynn Spears is pregnant by her boyfriend Casey Aldridge. Jamie Lynn is Britney Spears' younger sister, and at 16 she will be a "teen mother," but not a stereotypical one. Jamie Lynn Spears has her own television show and seems to have her shit "together." The stereotype is that the poor and those of lower SES are more likely to get pregnant as teens. That is statistically true:
Compared to teens from higher income families, poor and low-income teens are somewhat more likely to be sexually active and somewhat less likely to use contraceptives or to…
grrlscientist | December 17, 2007tags: Gene Genie, blog carnivals
The 22nd edition of the Gene Genie blog carnival is now available for you to enjoy. Of course, it is packed with all sorts of interesting stories for you to read, including one from moi!
gregladen | December 16, 2007
Every few years a paper comes out "explaining" short stature in one or more Pygmy groups. Most of the time the new work ads new information and new ideas but fails to be convincing. This is the case with the recent PNAS paper by Migliano et al.
From the abstract:
Every few years a paper comes out "explaining" short stature in one or more Pygmy groups. Most of the time the new work ads new information and new ideas but fails to be convincing. This is the case with the recent PNAS paper by Migliano et al.
From the abstract:
Explanations for the evolution of human pygmies continue to be a…
pharyngula | December 14, 2007
On the one hand, this is a strange tale of mutant, bisexual, necrophiliac flies, and you've got to love it for the titillating nature of the experiments. But on the other, much more interesting hand, it's a story about drilling down deeply into the causes of a complex behavior, and tracing it to a single gene product — and it also reveals much about the way the chemicals sloshing about in the brain can modulate responses to stimuli. Work by Grosjean and others on a simple Drosophila mutant, genderblind, which causes flies to be indiscriminate about gender in their courtship, opens up a…
razib | December 13, 2007A few years ago, a new paper, SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans, made some waves. It used zebrafish to elucidate the genetics of a locus, SLC24A5, which is responsible for 1/3 of the between population difference between Europeans and Africans in skin color. In short, Europeans are fixed for a derived variant, and Africans and East Asians for an ancestral one. Additionally, SLC24A5 shows up in tests for very recent (last 10,000 years) selection, and is implicated in 1/3 of the skin color variation in South Asians. Today, a similar paper which…
gregladen | December 13, 2007Fearless Mouse
In this undated photo released by Tokyo University's Department of Biophysics and Biochemistry Graduate School of Science, a genetically modified mouse stays near a cat in Tokyo. Using genetic engineering, scientists at Tokyo University say they have successfully switched off the rodents' instinct to cower at the smell or presence of cats, showing that fear is genetically hardwired and not leaned through experience, as commonly believed. (AP Photo/Ko and Reiko Kobayakawa, Tokyo University Department of Biophysics and Biochemistry Graduate School of Science)
[source]
... This…
gregladen | December 13, 2007The Central African Rainforest (as distinct from the West African Rain Forest) spans an area from the Atlantic coast to nearly Lake Victoria in Uganda and Tanzania. In fairly recent times (the mid Holocene) this forest was probably continuous all the way to Victoria, and probably extended farther north and south than one might imagine from looking at its current distribution.
Within the forest are major rivers, including the Congo. The Congo River is the only major river in the world that crosses the Equator twice. This trans-equatorial configuration guarantees that the rivers picks up…