Department of Biology, Ecology and Earth Science, University of Calabria, Via P. Bucci 4/B, 87036 Rende, Italy.
Independent Researcher, Via Michelangelo 123, 81031 Aversa, Italy.
Genes (Basel). 2024 Mar 18;15(3):371. doi: 10.3390/genes15030371.
Karyotype diversification represents an important, yet poorly understood, driver of evolution. Squamate reptiles are characterized by a high taxonomic diversity which is reflected at the karyotype level in terms of general structure, chromosome number and morphology, and insurgence of differentiated simple or multiple-sex-chromosome systems with either male or female heterogamety. The potential of squamate reptiles as unique model organisms in evolutionary cytogenetics has been recognised in recent years in several studies, which have provided novel insights into the chromosome evolutionary dynamics of different taxonomic groups. Here, we review and summarize the resulting complex, but promising, general picture from a systematic perspective, mapping some of the main squamate karyological characteristics onto their phylogenetic relationships. We highlight how all the major categories of balanced chromosome rearrangements contributed to the karyotype evolution in different taxonomic groups. We show that distinct karyotype evolutionary trends may occur, and coexist, with different frequencies in different clades. Finally, in light of the known squamate chromosome diversity and recent research advances, we discuss traditional and novel hypotheses on karyotype evolution and propose a scenario of circular karyotype evolution.
染色体组型多样化代表了进化的一个重要但尚未被充分理解的驱动因素。爬行动物蜥蜴类以高度的分类多样性为特征，这在染色体组型水平上反映为一般结构、染色体数目和形态，以及分化的简单或多性染色体系统的出现，这些系统具有雄性或雌性异型性。近年来，几项研究认识到爬行动物蜥蜴类作为进化细胞遗传学独特模型生物的潜力，这些研究为不同分类群的染色体进化动态提供了新的见解。在这里，我们从系统的角度回顾和总结由此产生的复杂但有希望的总体情况，将一些主要的蜥蜴类染色体特征映射到它们的系统发育关系上。我们强调了所有主要类别的平衡染色体重排如何为不同分类群的染色体组型进化做出贡献。我们表明，不同的染色体进化趋势可能以不同的频率在不同的进化枝中发生并共存。最后，根据已知的蜥蜴类染色体多样性和最近的研究进展，我们讨论了关于染色体组型进化的传统和新假说，并提出了循环染色体组型进化的情景。
