Vieira Cristina, Nardon Christiane, Arpin Christophe, Lepetit David, Biémont Christian
Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Université Lyon 1, Villeurbanne Cedex, France.
Mol Biol Evol. 2002 Jul;19(7):1154-61. doi: 10.1093/oxfordjournals.molbev.a004173.
Genome size varies considerably between species, and transposable elements (TEs) are known to play an important role in this variability. However, it is far from clear whether TEs are involved in genome size differences between populations within a given species. We show here that in Drosophila melanogaster and Drosophila simulans the size of the genome varies among populations and is correlated with the TE copy number on the chromosome arms. The TEs embedded within the heterochromatin do not seem to be involved directly in this phenomenon, although they may contribute to differences in genome size. Furthermore, genome size and TE content variations parallel the worldwide colonization of D. melanogaster species. No such relationship exists for the more recently dispersed D. simulans species, which indicates that a quantitative increase in the TEs in local populations and fly migration are sufficient to account for the increase in genome size, with no need for an adaptation hypothesis.
基因组大小在不同物种间差异很大，已知转座元件（TEs）在这种差异中起重要作用。然而，转座元件是否参与给定物种内不同种群间的基因组大小差异，目前还远不清楚。我们在此表明，在黑腹果蝇和拟暗果蝇中，基因组大小在不同种群间存在差异，且与染色体臂上的转座元件拷贝数相关。尽管异染色质中嵌入的转座元件可能导致基因组大小差异，但它们似乎并未直接参与这一现象。此外，基因组大小和转座元件含量的变化与黑腹果蝇物种在全球的定殖情况平行。对于较近期扩散的拟暗果蝇物种，不存在这样的关系，这表明当地种群中转座元件数量的定量增加和果蝇迁移足以解释基因组大小的增加，无需适应性假说。
