Primate colour vision depends on a matrix of photoreceptors, a neuronal post receptoral structure and a combination of genes that culminate in different sensitivity through the visual spectrum. Along with a common cone opsin gene for short wavelengths (sws1), Neotropical primates (Platyrrhini) have only one cone opsin gene for medium-long wavelengths (mws/lws) per X chromosome while Paleotropical primates (Catarrhini), including humans, have two active genes. Therefore, while female platyrrhines may be trichromats, males are always dichromats. The genus Alouatta is inferred to be an exception to this rule, as electrophysiological, behavioural and molecular analyses indicated a potential for male trichromacy in this genus. However, it is very important to ascertain by a combination of genetic and behavioural analyses whether this potential translates in terms of colour discrimination capability. We evaluated two howler monkeys (Alouatta spp.), one male A. caraya and one female A. seniculus, using a combination of genetic analysis of the opsin gene sequences and a behavioral colour discrimination test not previously used in this genus. Both individuals completed the behavioural test with performances typical of trichromatic colour vision and the genetic analysis of the sws1, mws, and lws opsin genes revealed three different opsin sequences in both subjects. These results are consistent with uniform trichromacy in both male and female, with presumed spectral sensitivity peaks similar to Catarrhini, at ~ 430 nm, 532 nm, and 563 nm for S-, M- and L-cones, respectively.

中文翻译：

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Alouatta caraya和Alouatta seniculus 的均匀三色性：行为和遗传色觉评估

灵长类动物的色觉取决于光感受器矩阵、神经元后感受器结构和基因组合，这些基因在视觉光谱中具有不同的敏感性。除了常见的短波长视锥视蛋白基因 (sws1) 外，新热带灵长类动物 (Platyrrhini) 的每个 X 染色体只有一个中长波长 (mws/lws) 视锥视蛋白基因，而古热带灵长类动物 (Catarrhini)，包括人类，有两个活性基因。因此，虽然雌性桔梗可能是三色视者，但雄性总是二色视者。Alouatta 属被推断为该规则的一个例外，因为电生理学、行为和分子分析表明该属有雄性三色性的潜力。然而，通过遗传和行为分析的结合来确定这种潜力是否转化为颜色辨别能力非常重要。我们评估了两只吼猴（Alouatta spp.），一只雄性 A. caraya 和一只雌性 A. seniculus，结合使用视蛋白基因序列的遗传分析和以前未在该属中使用的行为颜色辨别测试。两个人都完成了具有典型三色视觉表现的行为测试，并且对 sws1、mws 和 lws 视蛋白基因的遗传分析揭示了两个受试者的三种不同的视蛋白序列。这些结果与男性和女性的均匀三色性一致，假定的光谱灵敏度峰值与 Catarrhini 相似，分别为 S-、M-和 L-锥体的~430 nm、532 nm 和 563 nm。