Laboratory of Genetics, Wageningen University, Wageningen, the Netherlands.
Genome. 2012 Jan;55(1):15-25. doi: 10.1139/g11-071. Epub 2011 Dec 12.
Chromosomal rearrangements, including reciprocal translocations, may prevent recombinational transfer of genes from a donor genotype to a recipient, especially when the gene is located in an interstitial segment. The effect of trisomy of chromosome arm 1RS on recombination was studied in translocation heterozygote T248W of rye ( Secale cereale ), involving chromosome arms 1RS and 6RS. (Pro)metaphase I configuration frequencies were analyzed. Crossing over, estimated as chiasma parameters, in five genetically different euploid heterozygotes was compared with those of 10 different single arm trisomics. The addition of 1RS greatly altered the crossing over pattern around the translocation break point, with a special increase in the interstitial segment of 6RS and adjoining regions, normally hardly accessible to recombination. Furthermore, there was considerable variation between plants of closely related genotypes. Heterogeneity widens the distribution of crossing overs, including segments normally not accessible to recombination, but decreases average recombination in other segments. The extra chromosome and abnormal segregants are eliminated by using the trisomic as the pollen parent.
染色体重排，包括相互易位，可能会阻止基因从供体基因型向受体的重组转移，特别是当基因位于间区片段时。本研究以含有 1RS 和 6RS 染色体臂的黑麦 T248W 易位杂合体为材料，研究了 1RS 染色体臂三体对重组的影响。（Pro）中期 I 构型频率进行了分析。比较了 5 种不同遗传上不同的整倍体杂合体和 10 种不同的单臂三体的交换参数。1RS 的增加极大地改变了易位断点周围的交换模式，特别是在 6RS 的间区片段和邻近区域，通常很难发生重组。此外，亲缘关系密切的基因型之间的植物存在很大的差异。异质性扩大了交叉的分布，包括通常无法进行重组的片段，但会降低其他片段的平均重组率。通过使用三体作为花粉亲本，可以消除额外的染色体和异常的分离体。
