Instituto Nacional de Pesquisas da Amazônia, Coordenação de Biodiversidade, Laboratory of Animal Genetics, Av. André Araújo 2936, Petrópolis, Manaus CEP 69067-375, Brazil.
Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos SP 13565-090, Brazil.
Cells. 2020 Sep 12;9(9):2088. doi: 10.3390/cells9092088.
The Amazonian red side-necked turtle is an endemic Amazonian Chelidae species that occurs in small streams throughout Colombia and Brazil river basins. Little is known about various biological aspects of this species, including its sex determination strategies. Among chelids, the greatest karyotype diversity is found in the Neotropical species, with several 2 configurations, including cases of triploidy. Here, we investigate the karyotype of by applying combined conventional and molecular cytogenetic procedures. This allowed us to discover a genetic sex-determining mechanism that shares an ancestral micro XY sex chromosome system. This ancient micro XY system recruited distinct repeat motifs before it diverged from several South America and Australasian species. We propose that such a system dates back to the earliest lineages of the chelid species before the split of South America and Australasian lineages.
亚马逊红侧颈龟是一种仅分布于亚马逊河流域的淡水龟，分布于哥伦比亚和巴西的多条小流域中。目前对该物种的各种生物学特征了解甚少，包括其性别决定策略。在淡水龟科中，新热带物种的染色体组型多样性最大，有几种 2 型染色体，包括三倍体的情况。在这里，我们通过应用常规和分子细胞遗传学相结合的方法来研究 的染色体组型。这使我们发现了一种遗传性别决定机制，该机制共享一个古老的微 XY 性染色体系统。在与几个南美洲和澳大利亚物种分化之前，这个古老的微 XY 系统就招募了不同的重复基序。我们提出，这样的系统可以追溯到在南美和澳大利亚谱系分裂之前，在淡水龟科的最早谱系中。
