Department of Entomology, Texas A&M University, College Station, TX 77843, USA.
Department of Biology, Texas A&M University, College Station, TX 77843, USA.
Genes (Basel). 2020 Feb 19;11(2):218. doi: 10.3390/genes11020218.
Genome size varies widely across organisms yet has not been found to be related to organismal complexity in eukaryotes. While there is no evidence for a relationship with complexity, there is evidence to suggest that other phenotypic characteristics, such as nucleus size and cell-cycle time, are associated with genome size, body size, and development rate. However, what is unknown is how the selection for divergent phenotypic traits may indirectly affect genome size. were selected for small and large body size for up to 220 generations, while were selected for 32 generations for fast and slow development. Size in significantly changed in terms of both cell-count and genome size in isolines, but only the cell-count changed in lines which were maintained at larger effective population sizes. Larger genome sizes only occurred in a subset of isolines originated from flies selected for their large body size. Selection for development time did not change average genome size yet decreased the within-population variation in genome size with increasing generations of selection. This decrease in variation and convergence on a similar mean genome size was not in correspondence with phenotypic variation and suggests stabilizing selection on genome size in laboratory conditions.
基因组大小在生物体中差异很大，但在真核生物中尚未发现与生物体复杂性有关。虽然没有证据表明与复杂性有关，但有证据表明，其他表型特征，如核大小和细胞周期时间，与基因组大小、体型和发育速度有关。然而，尚不清楚选择不同的表型特征如何间接地影响基因组大小。在 220 多代中，选择了体型小和体型大的 ，而选择了体型大的 32 代，以实现快速和缓慢的发育。在隔离种群中，无论是细胞计数还是基因组大小，大小都发生了显著变化，但在有效种群大小较大的种群中，只有细胞计数发生了变化。只有一部分来自体型较大的果蝇的 隔离种群的基因组较大。选择发育时间不会改变平均基因组大小，但会随着选择世代的增加而降低基因组大小的种群内变异。这种变异的减少和对相似平均基因组大小的趋同，与表型变异不一致，表明在实验室条件下对基因组大小存在稳定选择。
