DNA差異研究顯示,，在人類的歷史長河里，少數(shù)的男性似乎比其他人在基因池里有著更多的遺傳表現(xiàn),。
由亞利桑那大學(xué)人口遺傳學(xué)家Michael Hammer領(lǐng)導(dǎo)的一個研究小組,，對分屬6組的90人進(jìn)行了DNA測序，這些人分別為：美拉尼西亞人（Melanesians）,，巴斯克人（Basques）,，漢族人，三組非洲居民——Mandenka,，Biaka和San ,。結(jié)果發(fā)現(xiàn)，X染色體上有較多的基因差異,，如果人類歷史中相同數(shù)量的男性和女性組成配偶的話,，X染色體的差異不會有那么大。Hammer說,，“大多數(shù)社會實現(xiàn)某種形式一夫多妻或一妻多夫”,。即使現(xiàn)代西方的男性只有一個妻子，但他們?nèi)匀幌牒透嗯陨⒆?，這種愿望比女性至于男性強烈的多,。研究顯示，現(xiàn)代的一夫一妻制甚至還沒有在我們基因中留下標(biāo)記,。Hamme說，“我不知道一夫一妻制實施了多久,，但從進(jìn)化上看不是很突出,。”
論文發(fā)表在開放獲取雜志《公共科學(xué)圖書館·遺傳學(xué)》（PLoS Genetics）上。（生物谷Bioon.com）
生物谷推薦原始出處：
PLoS Genetics,，4(9): e1000202. doi:10.1371/journal.pgen.1000202,，Michael F. Hammer, Jeffrey D. Wall
Sex-Biased Evolutionary Forces Shape Genomic Patterns of Human Diversity
Michael F. Hammer1,2*, Fernando L. Mendez2, Murray P. Cox1, August E. Woerner1, Jeffrey D. Wall3
Comparisons of levels of variability on the autosomes and X chromosome can be used to test hypotheses about factors influencing patterns of genomic variation. While a tremendous amount of nucleotide sequence data from across the genome is now available for multiple human populations, there has been no systematic effort to examine relative levels of neutral polymorphism on the X chromosome versus autosomes. We analyzed ~210 kb of DNA sequencing data representing 40 independent noncoding regions on the autosomes and X chromosome from each of 90 humans from six geographically diverse populations. We correct for differences in mutation rates between males and females by considering the ratio of within-human diversity to human-orangutan divergence. We find that relative levels of genetic variation are higher than expected on the X chromosome in all six human populations. We test a number of alternative hypotheses to explain the excess polymorphism on the X chromosome, including models of background selection, changes in population size, and sex-specific migration in a structured population. While each of these processes may have a small effect on the relative ratio of X-linked to autosomal diversity, our results point to a systematic difference between the sexes in the variance in reproductive success; namely, the widespread effects of polygyny in human populations. We conclude that factors leading to a lower male versus female effective population size must be considered as important demographic variables in efforts to construct models of human demographic history and for understanding the forces shaping patterns of human genomic variability.
