Saint-Leandre Bastien, Clavereau Isabelle, Hua-Van Aurelie, Capy Pierre
Laboratoire Evolution, Génomes, Comportement, Ecologie CNRS, Univ. Paris-Sud, IRD, Université Paris-Saclay, Gif-sur-Yvette Cedex, France.
Mol Ecol. 2017 Jul;26(14):3715-3731. doi: 10.1111/mec.14145. Epub 2017 Jun 24.
During colonization of new areas, natural populations have to deal with changing environments, and transposable elements (TEs) can be useful "tools" in the adaptation process as they are major contributor to the structural and functional evolution of genomes. In this general context, the activity (copy number, transcriptional and excision rate) of the mariner mos1 element was estimated in 19 natural populations of D. simulans. It is shown (i) that mos1 expression is always higher and more variable in testes than in ovaries; (ii) that mos1 activity is higher in colonizing populations compared to the sub-Saharan African ones (ancestral populations); (iii) that mos1 variations in transcript levels and copy number are negatively correlated with transcriptional variations of piRNA genes, aubergine and argonaute3. Furthermore, mos1 levels of expression in testes highly contrast with the low expression patterns of ago3. These results strongly suggest that the expression polymorphism of piRNA genes could be responsible for the mos1 variations, first between male and female germlines and second, according to the status of natural populations (colonizing or not). These results provide new perspectives about TEs and piRNA genes co-evolution in Drosophila germlines.
在新区域的定殖过程中，自然种群必须应对不断变化的环境，而转座元件（TEs）在适应过程中可能是有用的“工具”，因为它们是基因组结构和功能进化的主要贡献者。在这一总体背景下，对拟暗果蝇（D. simulans）的19个自然种群中水手mos1元件的活性（拷贝数、转录和切除率）进行了估计。结果表明：（i）mos1在睾丸中的表达总是高于卵巢，且变化更大；（ii）与撒哈拉以南非洲种群（祖先种群）相比，定殖种群中mos1的活性更高；（iii）转录水平和拷贝数的mos1变异与piRNA基因、茄子和AGO3的转录变异呈负相关。此外，睾丸中mos1的表达水平与ago3的低表达模式形成强烈对比。这些结果有力地表明，piRNA基因的表达多态性可能是导致mos1变异的原因，首先是在雄性和雌性生殖系之间，其次是根据自然种群的状态（是否定殖）。这些结果为果蝇生殖系中转座元件和piRNA基因的共同进化提供了新的视角。
