Study Suggest Genetic Connection to Same-sex Behavior, But Not to Genes
A large study suggests that genes are connected to homosexual behavior, but also found there is no gene that makes people gay.
The study is said to be the largest of its kind. Researchers examined genetic material and information about sexual experiences from more than 470,000 adults in the United States and Britain. The findings were published in Science magazine.
The researchers found there are thousands of genetic differences linked to same-sex sexual behavior. Most have a very small effect on a person's behavior.
However, the researchers said five of the genetic markers were more strongly linked with same-sex sexual behavior. The genetic differences, or variants, were more commonly found in people who reported having had a same-sex sexual experience at some time.
Some of the genetic variants found were present in both men and women. Two of the variants found in men were near genes involved in male hair loss and sense of smell.
About five percent of British participants and about 19 percent of U.S. persons who took part reported ever having a same-sex sexual experience. Those providing information for the study were not asked whether they identified themselves as gay or lesbian.
The research "provides the clearest glimpse yet" into the genetic reasons for same-sex sexual behavior, said study co-writer Benjamin Neale. He is a geneticist at the Broad Institute in Cambridge, Massachusetts.
But Neale also added, "We also found that it's effectively impossible to predict an individual's sexual behavior from their genome."
The researchers noted that the study centered on people's sexual behavior, and not on sexual identity. They also noted that the study only involved people whose ancestors were European. They could not answer whether similar results would be found in other groups.
The origins of same-sex behavior are unclear. Some of the strongest evidence of a genetic link comes from studies on twins. Many scientists believe that social, cultural, family and biological conditions are also involved. Some religious groups and other critics consider it a choice or a behavior that can be changed.
A Science magazine commentary notes that the five identified genetic variants had such a weak effect on behavior that using the results "for prediction, intervention or a supposed ‘cure' is wholly...impossible."
Experts not involved in the study had many reactions. Former National Institutes of Health geneticist Dean Hamer said the study confirms "that sexuality is complex and there are a lot of genes involved." But he added that the study was not "really about gay people."
"Having just a single same sex experience is completely different than actually being gay or lesbian," Hamer noted.
His research in the 1990s linked a marker on the X chromosome with male homosexuality. Later studies had similar results. The latest study, however, found no such link.
Doug Vanderlaan is a psychologist at the University of Toronto in Canada. He said the lack of information on sexual orientation is a weakness of the study.
The study was released on August 29. An international team of experts from Britain, the U.S., Europe and Australia carried out the research. They completed human genome examinations using blood samples from the UK Biobank and saliva samples from the U.S.-based ancestry company 23andMe. All samples were from individuals who had agreed to take part in the research.
I'm Anna Mateo.
1.carried out 实施
She successfully carried out her plan.
2.sexual behavior 性行为
The researchers don't yet know whether serotonin affects sexual behavior in female mice.
3.sex experience 性经验
She had two boy friends before and had the sex experience.
4.agreed to 同意
He agreed to go with me.
5.Most have a very small effect on a person's behavior.
have an effect on 对...有影响
I am sure that it will have an effect on our natural environment.
Climate and temperature have an effect on your intelligence.
6.All samples were from individuals who had agreed to take part in the research.
take part in 参加
They returned to take part in the season's opening game.
You don't need strength to take part in this sport.
这项研究据说是同类研究中规模最大的 。研究人员调查了美国和英国超过47万成年人的基因材料和性经验信息 。研究结果发表在《科学》杂志上 。
研究人员发现，有数千种基因差异与同性性行为有关 。而大多数对人的行为的影响很小 。
然而，研究人员表示，其中五种基因标记与同性性行为的联系更为紧密 。这种基因差异，或者变异，在有过同性性行为的人身上更为常见 。
一些基因变异在男性和女性身上都有体现 。在男性身上发现的两种变异基因与男性脱发和嗅觉有关 。
约5%的英国受试者和19%的美国受试者表示曾有过同性性行为 。那些为研究提供信息的人并未被问及是男同性恋还是女同性恋 。
这项研究的合著者本杰明·尼尔（Benjamin Neale）表示，这项研究“对同性性行为的基因原因提供了迄今为止最清晰的脉络” 。他是马萨诸塞州剑桥市布罗德研究所的遗传学家 。
研究人员指出，这项研究关注的是人们的性行为，而不是性身份 。他们还指出，这项研究只涉及欧洲人的后代 。他们无法肯定其他群体中是否会出现类似的结果 。
同性性行为的起源尚不清楚 。基因联系的一些最有力的证据来自对双胞胎的研究 。许多科学家认为，社会、文化、家庭和生物条件也有一定影响 。一些宗教团体和其他批评家认为这（同性性行为）是一种可改变的选择或行为 。
没有参与该项研究的专家纷纷对此做出回应 。美国国立卫生研究院前遗传学家迪恩·哈默(Dean Hamer)表示，这项研究证实，“性是复杂的，涉及到很多基因 。”但他补充说，这项研究并不是“真正针对同性恋者” 。
他的一项20世纪90年代的研究将X染色体上的一个标记与男性同性恋联系起来 。之后的研究也有类似的结果 。然而，最新的研究没有发现这种联系 。
Doug Vanderlaan是加拿大多伦多大学的心理学家 。他说，缺乏有关性取向的信息是这项研究的不足之处 。
这项研究于8月29日发表 。一个由英国、美国、欧洲和澳大利亚专家组成的国际团队进行了这项研究 。他们利用英国生物银行的血液样本以及位于美国的ancestry公司23andMe的唾液样本完成了人类基因组检测 。所有样本均来自同意参与研究的个人 。