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已有 2072 次阅读 2019-9-25 22:08 |系统分类:论文交流


No ‘gay gene’: Massive study homes in on genetic basis of human sexuality


副标题是这样写的:Nearly half a million genomes reveal five DNA markers associated with sexual behaviour — but none with the power to predict the sexuality of an individual. 

OK, 延续了标题给我的印象,性取向不是由基因决定的,找到一些标记,但无法预测的标记有啥用呢?


The largest study1 to date on the genetic basis of sexuality has revealed five spots on the human genome that are linked to same-sex sexual behaviour — but none of the markers are reliable enough to predict someone’s sexuality.


The findings, which are published on 29 August in Science and based on the genomes of nearly 500,000 people, shore up the results of earlier, smaller studies and confirm the suspicions of many scientists: while sexual preferences have a genetic component, no single gene has a large effect on sexual behaviours.

好嘛,刚发表的,还是Science, 近50万人的全基因组分析,与之前的、更小的研究,许多科学家的猜测一致,够有说服力了吧! 那他们究竟得出了什么结论呢?我尝试翻译一下:尽管性取向有遗传因素在里面,但并没有某一个基因在性行为上有很大的决定作用。



继续下一段:“There is no ‘gay gene’,” says lead study author Andrea Ganna, a geneticist at the Broad Institute of MIT and Harvard in Cambridge, Massachusetts.


Ganna and his colleagues also used the analysis to estimate that up to 25% of sexual behaviour can be explained by genetics, with the rest influenced by environmental and cultural factors — a figure similar to the findings of smaller studies.


The genetics of sexual orientation

Twin studies and other analyses of inheritance of sexual orientation in humans has indicated that same-sex sexual behavior has a genetic component. Previous searches for the specific genes involved have been underpowered and thus unable to detect genetic signals. Ganna et al. perform a genome-wide association study on 493,001 participants from the United States, the United Kingdom, and Sweden to study genes associated with sexual orientation (see the Perspective by Mills). They find multiple loci implicated in same-sex sexual behavior indicating that, like other behavioral traits, nonheterosexual behavior is polygenic.

感觉立场很不一样,这里强调的是大规模和多基因性,但这句“like other behavioral traits”不知道是臧是否。这是一句事实性的描述,看读者怎么理解。你可以说同性行为跟其他许多行为一样,是由多基因决定的,我们不应该把它作为一个什么特殊的行为。也可以理解为同性行为跟其他许多行为一样,并没有什么决定基因,所以是可以后天怎样怎样的。


原文的结构式摘要(Structured Abstract)的结果部分是这样写的:

In the discovery samples (UK Biobank and 23andMe), five autosomal loci were significantly associated with same-sex sexual behavior. 
在我们所分析的来自UK Biobank 和 23andMe样本里,五个来自常染色体的位点与同性行为有显著关联。

Follow-up of these loci suggested links to biological pathways that involve sex hormone regulation and olfaction. 

Three of the loci were significant in a meta-analysis of smaller, independent replication samples. 
其中有三个位点在另一个更小的、独立的荟萃分析样本集中仍然显著。(~5000人,Wald test P值三者为0.027, 0.003, 0.006)

Although only a few loci passed the stringent statistical corrections for genome-wide multiple testing and were replicated in other samples, our analyses show that many loci underlie same-sex sexual behavior in both sexes. 

In aggregate, all tested genetic variants accounted for 8 to 25% of variation in male and female same-sex sexual behavior, and the genetic influences were positively but imperfectly correlated between the sexes [genetic correlation coefficient (rg)= 0.63; 95% confidence intervals, 0.48 to 0.78]. 
Nevertheless, the contribution of all measured common SNPs in aggregate (SNP- based heritability) was estimated to be 8 to 25% (95% CIs, 5 to 30%) of variation in female and male same-sex sexual behavior, in which the range reflects differing estimates by using different analysis methods or prevalence assumptions (table S11) (14) 
将所有经过检验的,两个数据集(UK Biobank和23andMe)里共有的单核苷酸多样性(SNPs)数据的效用加起来,共能解释8-25%的与同性行为(无论男女),这个范围反映了基于不同流行率假定下的不同计算方法所得出的结果。(看来25%还是最高估计啊)


These aggregate genetic influences partly overlapped with those on a variety of other traits, including externalizing behaviors such as smoking, cannabis use, risk-taking, and the personality trait openness to experience. 

Additional analyses suggested that sexual behavior, attraction, identity, and fantasies are influenced by a similar set of genetic variants (rg > 0.83); 
进一步的分析表明,影响性行为、性吸引、性身份以及性幻想的遗传变异组成相似(r> 0.83);

however, the genetic effects that differentiate heterosexual from same-sex sexual behavior are not the same as those that differ among nonheterosexuals with lower versus higher proportions of same-sex partners, which suggests that there is no single continuum from opposite-sex to same-sex preference. 



Same-sex sexual behavior is influenced by not one or a few genes but many. 
同性行为不止受到一个或几个基因的影响,而是很多个(no "gay gene").

Overlap with genetic influences on other traits provides insights into the underlying biology of same-sex sexual behavior, 

and analysis of different aspects of sexual preference underscore its complexity and call into question the validity of bipolar continuum measures such as the Kinsey scale. 

Nevertheless, many uncertainties remain to be explored, including how sociocultural influences on sexual preference might interact with genetic influences. 

To help communicate our study to the broader public, we organized workshops in which representatives of the public, activists, and researchers discussed the rationale, results, and implications of our study. 

The discrepancy between the variance captured by the significant SNPs and all common SNPs suggests that same-sex sexual behavior, like most complex human traits, is influenced by the small, additive effects of very many genetic variants, most of which cannot be detected at the current sample size (22). 

面对这样的结果,我实在无法赞同Nature新闻标题里的“homes in”这个说法。感觉未知还是大于已知。如果想了解更多该实验的背景,推荐哈佛大学杂志的


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