The color vision typing using fecal DNA of New World monkeys and the analysis of vision-behavior relatedness

新世界猴的色觉多态性是由位于x染色体上的单位点中-长波敏感视蛋白（M/LWS）等位基因变异引起的。这种多态性是跨特异性的，因此一般认为是由某种形式的平衡选择维持的。然而，平衡选择的存在尚未得到群体遗传参数的严格检验。在通常不超过几十个人的社会群体层面上，色觉多态性的存在与否并没有得到很好的评估。此外，在新向性环境中，三色视觉对灵长类动物的优势并不完全清楚，因为许多全年可用的食物资源对人类观察者来说似乎是神秘的。为了研究新世界猴色觉多态性持续存在的机制，我们研究了哥斯达黎加圣罗莎国家公园的白面卷尾猴（Cebus capucinus）和黑手蜘蛛猴（Ateles geoffroyi）。我们采取了三管齐下的方法：(1)利用粪便DNA对M/LWS视蛋白等位基因进行基因分型来评估社会群体的色觉多态性；(2)通过评估M/LWS视蛋白基因的核苷酸多样性来检验中性假设；(3)通过寻找色觉类型与觅食等行为模式之间的相关性来评估色觉变异的行为意义。研究发现：(1)卷尾猴和蜘蛛猴群体中确实存在色觉多态性，但在群体和种之间存在不同的等位基因组成；(2)M/LWS视蛋白基因Tajima的D统计量显著阳性，而在中性对照中则不显著阳性；(3)二色卷尾猴在昆虫觅食方面效率更高，水果的颜色可能不是三色蜘蛛猴的关键线索。这些结果表明，高水平的色觉多态性只能通过某种形式的平衡选择来解释，这可能包括杂合子（=三色）优势以外的因素。少

Color vision polymorphism in New World monkeys results from allelic variation of the single-locus middle-to-long-wave-sensitive (M/LWS) opsin gene residing on the X-chromosome. This polymorphism is trans-specific, and thus generally believed to be maintained by some form of balancing selection. However, the presence of balancing selection has not been tested rigorously by population genetic parameters. At the level of a social group, which usually comprises no more than a few dozen individuals, presence or absence of color vision polymorphism is not well assessed. In addition, the advantage of trichromacy to primates is not entirely clear in the Neotropic environment, since many of the food resources that are available throughout the year appear cryptic to human observers.To investigate the mechanism behind the persistence of color vision polymorphism in New World monkeys, we examined free-ranging populations of white-faced capuchin monkeys (Cebus capucinus) and black-handed spider mon … More keys (Ateles geoffroyi) inhabiting Santa Rosa National Park, Costa Rica. We took a three-pronged approach : (1) assessment of color vision polymorphism in social groups by genotyping M/LWS opsin alleles using fecal DNA, (2) tests of the neutral hypothesis by evaluating nucleotide diversity of the M/LWS opsin gene, and (3) assessment of the behavioral significance of color vision variation by looking for correlations between color vision type and behavioral patterns such as foraging.We found that : (1) color vision polymorphism is indeed present in both capuchin and spider monkey groups, each comprising only 〜20 individuals, but with various allele compositions between groups and between species, (2) Tajima's D statistic is significantly positive for M/LWS opsin gene but it is not for the neutral controls, and (3) dichromatic capuchins are more efficient at insect foraging, and hue of fruits may not be a critical cue for trichromatic spider monkeys. These results indicate that the high level of color vision polymorphism can be explained only by some form of balancing selection, which would likely include factors other than heterozygote (= trichromat) advantage. Less