The two breakpoints of a chromosomal inversion fixed since the split of Drosophila melanogaster and D. subobscura lineages have been isolated and sequenced in both species. The regions spanning the breakpoints initially were identified by the presence of two signals after interspecific in situ hybridization on polytene chromosomes. Interspecific comparison of the sequenced regions allowed us to delineate the location of the breakpoints. Close to one of these breakpoints a new transcription unit (bcn92) has been identified in both species. The inversion fixed between D. melanogaster and D. subobscura does not seem to have broken any transcription unit. Neither complete nor defective transposable elements were found in the regions encompassing the breakpoints. Short thymine-rich sequences (30-50 bp long) have been found bordering the breakpoint regions. Although alternating Pur-Pyr sequences were detected, these putative target sites for topoisomerase II were not differentially clustered in the breakpoints.
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机译：自果蝇和D.subobscura血统的分裂以来，染色体倒置的两个断点已被固定并在两个物种中进行了测序。跨断点的区域最初是通过在聚丙烯染色体上进行种间原位杂交后是否存在两个信号来识别的。测序区域的种间比较使我们能够描述断点的位置。接近这些断点之一，在这两个物种中都发现了一个新的转录单位（bcn92）。 D. melanogaster和D. subobscura之间固定的反演似乎没有破坏任何转录单位。在包含断点的区域中未发现完整或有缺陷的转座元件。已经发现短的富胸腺嘧啶序列（长30-50 bp）与断点区域接壤。尽管检测到交替的Pur-Pyr序列，但拓扑异构酶II的这些假定靶位点在断点处没有差异性聚集。
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