Реферат: Does A Gay Gene Exist Essay Research

Does A Gay Gene Exist Essay, Research Paper

Does A Gay Gene exist? Two possible ways the genetic material for

homosexuality may be transmitted

J. Michael Bailey of Northwestern U. and Richard C. Pillard of

Boston U. did a study on 161 gay men. Each had at least one

identical twin or fraternal twin or adopted brother. Fifty two

percent of the identical twins were also homosexual, as compared

with twenty two percent of the fraternal twins and eleven percent

of the adopted brothers. Similar studies have been done by Dean

Hammer and others with the same results. If one of the identical

twins is gay, then there is over a fifty- percent likely hood

that the other will also be gay. This is strong evidence that

homosexuality has at least a partial basis of inheritance. Thus,

a search began to find the gay gene(s).

Dean hammer noted that a seemingly high number of homosexual

men that he studied had gay uncles on their mother s side. He

speculated that the gay gene(s) might be located on the X

chromosome. Hammer examined X-chromosomes of gay men, trying to

find any differences with the X-chromosomes of heterosexual men.

In the region Xq28, he found a pattern that was common to many

homosexuals. Two thirds of the gay men that he tested had that

pattern. That would explain the reoccurrence of the gene despite

its negative selection (homosexuals tend not to have children).

Since males have only one X chromosome(compared with females who

have two), the genes on the chromosome are more likely to be

expressed. Hence, a man with the Xq28 has a greater chance of

being gay. As for women, presence of Xq28 does not seem to affect

sexual preference. That may be due to their extra X or that the

genes simply might not express themselves the same way in women.

--> ЧИТАТЬ ПОЛНОСТЬЮ <--