Genome Size in North American Fireflies: Substantial Variation Likely Driven by Neutral Processes.
Genome Size in North American Fireflies: Substantial Variation Likely Driven by Neutral Processes.
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DOI：
10.1093/gbe/evx097
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发表时间：
2017-06-01
影响因子：
3.3
通讯作者：
Hall D
中科院分区：
文献类型：
--
作者：
Lower SS;Johnston JS;Stanger-Hall KF;Hjelmen CE;Hanrahan SJ;Korunes K;Hall D
真核生物基因组在不同分类群中表现出巨大的大小差异。对基因组大小变异的直接解释包括倍性和非编码 DNA（尤其是重复 DNA）数量的差异。最终的解释包括对基因组大小的生理相关性（例如细胞大小）的选择，这反过来又影响身体大小，从而导致经常观察到的身体大小和基因组大小之间的相关性。在这项研究中，我们检查了北美单一甲虫科萤火虫科代表的体型大小和重复 DNA 元件与基因组大小进化的关系。所考虑的 23 个物种代表了一个出色的研究系统，因为基因组大小范围超过 5 倍（此处使用流式细胞术记录），体型大小范围超过 3 倍（使用前胸背板宽度测量）。我们还使用低覆盖率测序鉴定了常见的基因组重复元件。我们发现基因组大小和重复 DNA（尤其是逆转录转座子）之间存在正相关关系。考虑到系统发育相关性，基因组大小和这些元素都在按预期进化。我们还测试了基因组大小是否随身体大小变化，但没有发现任何关系。总之，我们的结果表明，萤火虫的基因组大小是中性进化的。
Eukaryotic genomes show tremendous size variation across taxa. Proximate explanations for genome size variation include differences in ploidy and amounts of noncoding DNA, especially repetitive DNA. Ultimate explanations include selection on physiological correlates of genome size such as cell size, which in turn influence body size, resulting in the often-observed correlation between body size and genome size. In this study, we examined body size and repetitive DNA elements in relationship to the evolution of genome size in North American representatives of a single beetle family, the Lampyridae (fireflies). The 23 species considered represent an excellent study system because of the greater than 5-fold range of genome sizes, documented here using flow cytometry, and the 3-fold range in body size, measured using pronotum width. We also identified common genomic repetitive elements using low-coverage sequencing. We found a positive relationship between genome size and repetitive DNA, particularly retrotransposons. Both genome size and these elements were evolving as expected given phylogenetic relatedness. We also tested whether genome size varied with body size and found no relationship. Together, our results suggest that genome size is evolving neutrally in fireflies.