Complex traits include, among many others, the evolution of eyes, wings, body forms, reproductive modes, human intelligence, social behavior, diseases, and chromosome morphology. Dollo's law states that the evolution of complex traits is irreversible. However, potential exceptions have been proposed. Here, we investigated whether reticulation, a simple and elegant means by which complex characters may be reacquired, could account for suggested reversals in the evolution of complex characters using two datasets with sufficient genetic coverage and a total of five potential reversals. Our analyses uncovered a potential reversal in the evolution of parity mode and a potential reversal in the evolution of placentotrophy of fish (Cyprinodontiformes) as reticulation events. Moreover, in a reptile that exhibits a potential reversal from viviparity to oviparity (Zootoca vivipara), reticulation provided the most parsimonious explanation for sex chromosome evolution. Therefore, three of the five studied potential reversals were unraveled as reticulation events. This constitutes the first evidence that accounting for reticulation can fundamentally influence the interpretation of the evolution of complex traits, that testing for reticulation is crucial for obtaining robust phylogenies, and that complex ancestral characters may be reacquired through hybridization with a lineage that still exhibits the trait. Hybridization, rather than reappearance of ancestral traits by means of small evolutionary steps, may thus account for suggested exceptions to Dollo's law. Consequently, ruling out reticulation is required to claim the evolutionary reversal of complex characters and potential exceptions to Dollo's rule.

中文翻译：

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网状事件揭示了复杂性状的逆转：奇偶校验模式，染色体形态和母体资源转移的经验教训。

复杂的特征包括眼睛，翅膀，身体形态，生殖方式，人类智力，社会行为，疾病和染色体形态的进化。多洛定律指出，复杂特征的演化是不可逆的。但是，已经提出了潜在的例外情况。在这里，我们调查了网纹（一种简单而优雅的方法，可以用来获取复杂字符）使用两个具有足够遗传覆盖范围的数据集和总共五个潜在的反向数据来解释复杂字符演变中的建议逆转。我们的分析揭示了作为网状事件的奇偶校验模式演化中的潜在逆转和鱼类（鲤齿形）胎盘营养素中潜在的逆转。此外，在表现出从胎生到卵生（Zootoca vivipara）的潜在逆转的爬行动物中，网状结构为性染色体进化提供了最简约的解释。因此，在五个研究的潜在逆转中，有三个作为网状事件被揭示。这构成了第一个证据，说明网状结构可以从根本上影响对复杂性状进化的解释，对网状结构的测试对于获得稳固的系统发育至关重要，并且可以通过与仍然具有该性状的谱系杂交来获得复杂的祖先性格。因此，杂交，而不是通过小的进化步骤重新出现祖先特征，可能会导致建议的多洛定律例外。所以，