Symington L S, Petes T D
Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637.
Mol Cell Biol. 1988 Feb;8(2):595-604. doi: 10.1128/mcb.8.2.595-604.1988.
To examine the relationship between genetic and physical chromosome maps, we constructed a diploid strain of the yeast Saccharomyces cerevisiae heterozygous for 12 restriction site mutations within a 23-kilobase (5-centimorgan) interval of chromosome III. Crossovers were not uniformly distributed along the chromosome, one interval containing significantly more and one interval significantly fewer crossovers than expected. One-third of these crossovers occurred within 6 kilobases of the centromere. Approximately half of the exchanges were associated with gene conversion events. The minimum length of gene conversion tracts varied from 4 base pairs to more than 12 kilobases, and these tracts were nonuniformly distributed along the chromosome. We conclude that the chromosomal sequence or structure has a dramatic effect on meiotic recombination.
为了研究遗传染色体图谱与物理染色体图谱之间的关系，我们构建了酿酒酵母的二倍体菌株，该菌株在第三条染色体23千碱基（5厘摩）区间内的12个限制性酶切位点突变处呈杂合状态。交叉在染色体上并非均匀分布，一个区间的交叉数量显著多于预期，而另一个区间则显著少于预期。其中三分之一的交叉发生在着丝粒的6千碱基范围内。大约一半的交换与基因转换事件相关。基因转换片段的最小长度从4个碱基对到超过12千碱基不等，并且这些片段在染色体上的分布并不均匀。我们得出结论，染色体序列或结构对减数分裂重组有显著影响。
