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Ursprungligen postat av
bottenslam
Vad är det som säger att genuttrycket är medfött och inte något som uppstår senare?
I våras så läste jag en sammanfattning av forskning på karolinska som visade att genuttrycket/genuttrycken som har kopplats till övervikt försvann efter gastricbypassoperation. Vilket i mina ögon tyder på att genuttryck är ett svar på omständigheter snarare än orsak. Det är också mer logiskt eftersom en homo-gen borde vara utgallrad ur människans genom för länge sen av naturliga skäl.
Så kan man uttrycka det ja. Särskilt gäller detta under påverkan av testosteron. Dock sker detta under tiden fostret befinner sig i uterus , så ska man vara korrekt är det medfött, hos ca 8 % av befolkningen generellt sett.
Dock har man nu även intresserat sig i vilka kromosompar dessa gener finns och hur det fungerar.
"The latest study involves about three times as many people as the previous largest study, which means it is significantly more statistically robust.
Over the past five years, Sanders has collected blood and saliva samples from 409 pairs of gay brothers, including non-identical twins, from 384 families. This compares, for example, with 40 pairs of brothers recruited for Hamer's study.
The team combed through the samples, looking at the locations of genetic markers called single nucleotide polymorphisms (SNPs) – differences of a single letter in the genetic code – and measuring the extent to which each of the SNPs were shared by the men in the study.
The only trait unequivocally shared by all 818 men was being gay. All other traits, such as hair colour, height and intelligence, varied by different degrees between each brothers in a pair and between all sets of brothers. Therefore, any SNPs consistently found in the same genetic locations across the group would most likely be associated with sexual orientation.
Only five SNPs stood out and of these, the ones most commonly shared were from the Xq28 and 8q12 regions on the X chromosome and chromosome 8 respectively. But this doesn't mean the study found two "gay genes". Both regions contain many genes, and the next step will be to home in on which ones might be contributing to sexual orientation."
Journal reference: Psychological Medicine, DOI: 10.1017/S0033291714002451