Sexual health – New genetic regions associated with male sexual orientation found
Our Health News
January 28, 2005 – The genes of a man by his father and mother can play an important role in determining whether he is gay or not play games, according to a new study, probably the "gay-gene reignite" debate.
The researchers say this is the first time the entire human genome in search of possible genetic determinants of male sexual orientation was scanned. The results suggest that several genetic regions may influence homosexuality.
"It is to previous studies that have found consistent evidence of genetic influence on sexual orientation, builds, but our study is the first to exactly where these genes are, look," says researcher Brian Mustanski, PhD, a psychologist at the University of Illinois at Chicago.
These previous studies looked only genes on the X chromosome localized. Genes on the chromosome passed only son of his mother. But this study examined genetic information on all chromosomes, including genes from the father.
The results show that identical stretches of DNA on three chromosomes were approximately 60% of gay brothers in the study, compared to approximately 50% will normally be expected by chance shared.
Gay gene debate
A heated debate about the existence of a "gay gene" came from a 1993 report published in the journal Science by the NIH researcher Dean Hamer then, PhD. This study linked DNA markers on the X chromosome of male sexual orientation.
Since then, questions about the validity of these results. Other researchers try to replicate Hamer’s findings and review. Hammer is also lead author of the study, published in the March issue of Human Genetics.
But the researchers say this study a different approach. His goal was not to replicate these findings, but are looking for new genetic markers associated with male sexual orientation.
"Since sexual orientation is a complex function, we will never be a gene, or someone is gay or not, are determined," says Mustanski. "It’s a combination of different genes act together, and the possible interaction with environmental influences to be."
Previous studies in male twins have suggested that between 40% -60% due to the variability in sexual orientation of genes. The rest is probably due to its environment and possibly other biological but not genetic causes.
Search for Gay Genes
In the study, researchers analyzed the genomes of 456 people 146 households with two or more gay brothers.
The genetic scans showed a clustering of the same genetic pattern among gay men on three chromosomes – chromosomes 7, 8 and 10 These common genetic patterns were shared by 60% of gay men in the study. This is expected to exceed 50% by chance alone.
The regions on chromosome 7 and 8 were associated with male sexual orientation, whether the man was his mother or father. The regions on chromosome 10 were only associated with male sexual orientation if they are inherited from the mother.
Mustanski, the study compares the approach of a search for doctors in a town of 40,000 people, a figure roughly equal to the number of human genes.
Rather than have to guess that the doctors live in a certain type of house and will only homes that would be the criteria, researchers in this scenario, knock on every door to vragen om residents at meetings if a doctor living in their straat . With a similar approach, the researchers could a number of possible genetic neighborhoods, contributing probably to be found, male sexual orientation.
Researchers say that the next step is to verify these findings in another group of men, or the same genetic regions associated with sexual orientation. If the results hold up, then Mustanski says they were for the individual genes in these regions with regard to sexual orientation search.
New goals for the Gay Gene Research
Elliot S. Gershon, MD, professor of psychiatry and human genetics at the University of Chicago, said the study represents an important advance in understanding how genes influence human sexual orientation.
"It’s worth testing genes within a region to the link to see if one of them has a variant more often in men than in homosexual men who do not," says Gerson, who is currently also involved in another study, gay Brothers and genetic influences on sexual orientation.
"This report contributes to the legitimacy of research on normal variations in human behavior," Gershon told us. "It is an argument in the public press that it is not appropriate, conditions or characteristics, behavioral studies have been made. But this suggests a genetic contribution to this special feature of the same sex orientation."
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Is there a "gay gene"?