Kraft T, Säll T, Magnusson-Rading I, Nilsson N O, Halldén C
Department of Genetics, Lund University, S-223 62 Lund, Sweden.
Genetics. 1998 Nov;150(3):1239-44. doi: 10.1093/genetics/150.3.1239.
The relation between the level of genetic variation and the rate of recombination per physical unit was investigated in sea beet (Beta vulgaris subsp. maritima). The rate of recombination per physical unit was estimated indirectly through marker density in an RFLP linkage map of sugar beet. From this map, we also selected RFLP markers covering two of the nine chromosomes in Beta. The markers were used to estimate the level of genetic variation in three populations of sea beet, two from Italy and one from England. Two estimates of genetic variation were employed, one based on the number of alleles in the sample and the other on heterozygosity. A statistically significant positive correlation was found between recombination rate and genetic variation. Several theoretical explanations for this are discussed, background selection being one. A correlation similar to this has been observed previously in Drosophila, one that was higher than what we obtained for Beta. This is consistent with various biological differences between the two species.
我们研究了海甜菜（Beta vulgaris subsp. maritima）中遗传变异水平与每物理单位重组率之间的关系。每物理单位的重组率是通过甜菜的RFLP连锁图谱中的标记密度间接估计的。从该图谱中，我们还选择了覆盖甜菜九条染色体中两条染色体的RFLP标记。这些标记用于估计三个海甜菜种群的遗传变异水平，其中两个种群来自意大利，一个来自英国。我们采用了两种遗传变异估计方法，一种基于样本中的等位基因数量，另一种基于杂合性。结果发现重组率与遗传变异之间存在统计学上显著的正相关。文中讨论了对此的几种理论解释，背景选择是其中之一。此前在果蝇中也观察到了类似的相关性，且果蝇中的相关性高于我们在甜菜中获得的相关性。这与两个物种之间的各种生物学差异是一致的。
