Ecology, Evolution and Developmental Group, Department of Wetland Ecology, Estación Biológica de Doñana (CSIC), Sevilla, Spain.
Department of Life Sciences, Natural History Museum, London, UK.
Nat Ecol Evol. 2018 Nov;2(11):1792-1799. doi: 10.1038/s41559-018-0674-4. Epub 2018 Sep 24.
The evolution and great diversity of genome size has been of long-standing interest to biologists, but has seldom been investigated on a broad phylogenetic scale. Here we present a comparative quantitative analysis of factors shaping genome size evolution in amphibians, the extant class of vertebrates with the largest variation in genome size. We find that amphibian genomes have undergone saltations in size, although these are rare and the evolutionary history of genome size in amphibians has otherwise been one of gradual, time-dependent variation (that is, Brownian motion). This macroevolutionary homogeneity is remarkable given the evolutionary and ecological diversity of most other aspects of the natural history of amphibians. Contrary to previous claims, we find no evidence for associations between life cycle complexity and genome size despite the high diversity of reproductive modes and the multiple events of independent evolution of divergent life cycles in the group. Climate (temperature and humidity) affects genome size indirectly, at least in frogs, as a consequence of its effect on premetamorphic developmental period, although directionality of the relationship between developmental period and genome size is not unequivocal.
基因组大小的进化和多样性一直是生物学家感兴趣的长期课题，但在广泛的系统发育尺度上很少有研究。在这里，我们对影响两栖类（现存脊椎动物中基因组大小变化最大的类群）基因组大小进化的因素进行了比较定量分析。我们发现，两栖动物的基因组大小发生了跳跃式变化，尽管这种情况很少见，而且两栖动物的基因组大小进化史在其他方面一直是渐进的、随时间变化的（即布朗运动）。鉴于大多数其他方面的自然历史具有多样性，这种宏观进化的同质性是显著的。与之前的说法相反，尽管该群体的生殖模式具有高度多样性，而且独立进化出了不同的生殖周期，但我们没有发现生命周期复杂性与基因组大小之间存在关联的证据。气候（温度和湿度）通过对前变态发育期的影响间接影响基因组大小，尽管发育期和基因组大小之间的关系方向并不明确。
