Montchamp-Moreau C, Ronsseray S, Jacques M, Lehmann M, Anxolabéhère D
Département Dynamique du Génome et Evolution, Institut J. Monod, CNRS-Université, Paris, France.
Mol Biol Evol. 1993 Jul;10(4):791-803. doi: 10.1093/oxfordjournals.molbev.a040049.
The distribution of 1731 retrotransposon-hybridizing sequences in the family Drosophilidae has been studied using a 1731 probe from Drosophila melanogaster. Squash blot and Southern blot analyses of 42 species reveal that the 1731 sequences are widespread within both the Sophophora and Drosophila subgenera and are also present in the genera Scaptomyza and Zaprionus. Hence the 1731 retrotransposon family appears to have a long evolutionary history in the Drosophilidae genome. Differences of hybridization signal intensity suggested that the 1731 sequence is well conserved only in the three species most closely related to D. melanogaster (D. simulans, D. mauritiana, and D. sechellia). A survey of insertion sites in numerous different populations of the previous four species by in situ hybridization to polytene chromosomes has shown in all cases both chromocentric hybridizations and a low number of sites (0-5) on the chromosomal arms. This number of sites is among the lowest observed in D. melanogaster and D. simulans when 1731 is compared with other retrotransposon families. In addition, we have observed species-specific patterns of the chromocentric hybridization signal, suggesting rapid modifications of the beta-heterochromatin components since the radiation of the melanogaster subgroup.
利用来自黑腹果蝇的1731探针，研究了1731个反转录转座子杂交序列在果蝇科中的分布情况。对42个物种的压片印迹和Southern印迹分析表明，1731序列在Sophophora亚属和果蝇亚属中广泛存在，也存在于Scaptomyza属和Zaprionus属中。因此，1731反转录转座子家族似乎在果蝇科基因组中有着悠久的进化历史。杂交信号强度的差异表明，1731序列仅在与黑腹果蝇关系最密切的三个物种（拟果蝇、毛里求斯果蝇和塞舌尔果蝇）中高度保守。通过对多线染色体进行原位杂交，对上述前四个物种的众多不同种群中的插入位点进行了调查，结果表明，在所有情况下，都存在着着丝粒杂交以及染色体臂上数量较少的位点（0 - 5个）。与其他反转录转座子家族相比，当比较1731时，这个位点数量在黑腹果蝇和拟果蝇中是观察到的最低数量之一。此外，我们还观察到了着丝粒杂交信号的物种特异性模式，这表明自黑腹果蝇亚群分化以来，β - 异染色质成分发生了快速变化。
