Sniegowski P D, Pringle A, Hughes K A
Department of Ecology and Evolution, University of Chicago, Illinois 60637.
Genet Res. 1994 Feb;63(1):57-62. doi: 10.1017/s0016672300032080.
We have investigated the interchromosomal effect of the naturally-occurring paracentric inversions In(2L)t and In(3R)P on meiotic recombination in two regions of the X chromosome in Drosophila melanogaster. Previous authors have suggested that the rate of recombination at the tip of the X chromosome may be substantially higher in some natural populations than values measured in the laboratory, due to the interchromosomal effect of heterozygous autosomal inversions. This suggestion was motivated by observations that transposable elements are not as common at the tip of the X chromosome as predicted by recent research relating reduced meiotic exchange to increased element abundance in D. melanogaster. We examined the effects of heterozygous In(2L)t and In(3R)P on recombination at both the tip and base of the X chromosome on a background of isogenic major chromosomes from a natural population. Both inversions substantially increased the rate of recombination at the base; neither one affected recombination at the tip. The results suggest that the presence of inversions in the study population does not elevate rates of crossing over at the tip of the X chromosome. The relevance of these results to ideas relating transposable element abundance to recombination rates is discussed.
我们研究了自然发生的臂内倒位In(2L)t和In(3R)P对黑腹果蝇X染色体两个区域减数分裂重组的染色体间效应。先前的作者认为，由于杂合常染色体倒位的染色体间效应，在某些自然种群中，X染色体末端的重组率可能显著高于在实验室中测得的值。这一观点的依据是，观察到转座元件在X染色体末端并不像最近关于减数分裂交换减少与黑腹果蝇元件丰度增加相关的研究所预测的那样常见。我们在来自自然种群的同基因主要染色体背景下，研究了杂合In(2L)t和In(3R)P对X染色体末端和基部重组的影响。两种倒位都显著提高了基部的重组率；两者都不影响末端的重组。结果表明，研究种群中倒位的存在不会提高X染色体末端的交叉率。讨论了这些结果与转座元件丰度与重组率相关观点的相关性。
