Kowalski S P, Lan T H, Feldmann K A, Paterson A H
Department of Soil and Crop Sciences, Texas A&M University, College Station 77843-2474.
Genetics. 1994 Oct;138(2):499-510. doi: 10.1093/genetics/138.2.499.
The chromosomes of Arabidopsis thaliana and Brassica oleracea have been extensively rearranged since the divergence of these species; however, conserved regions are evident. Eleven regions of conserved organization were detected, ranging from 3.7 to 49.6 cM in A. thaliana, spanning 158.2 cM (24.6%) of the A. thaliana genome, and 245 cM (29.9%) of the B. oleracea genome. At least 17 translocations and 9 inversions distinguish the genomes of A. thaliana and B. oleracea. In one case B. oleracea homoeologs show a common marker order, which is distinguished from the A. thaliana order by a rearrangement, indicating that the lineages of A. thaliana and B. oleracea diverged prior to chromosomal duplication in the Brassica lineage (for at least this chromosome). Some chromosomal segments in B. oleracea appear to be triplicated, indicating the need for reevaluation of a classical model for Brassica chromosome evolution by duplication. The distribution of duplicated loci mapped for about 13% of the DNA probes studied in A. thaliana suggests that ancient duplications may also have occurred in Arabidopsis. The degree of chromosomal divergence between A. thaliana and B. oleracea appears greater than that found in other confamilial species for which comparative maps are available.
自拟南芥和甘蓝分化以来，它们的染色体发生了广泛的重排；然而，保守区域依然明显。共检测到11个保守组织区域，在拟南芥中长度为3.7至49.6厘摩，跨越拟南芥基因组的158.2厘摩（24.6%）以及甘蓝基因组的245厘摩（29.9%）。至少17次易位和9次倒位区分了拟南芥和甘蓝的基因组。在一个案例中，甘蓝的同源基因显示出一种共同的标记顺序，该顺序与拟南芥的顺序因一次重排而不同，这表明拟南芥和甘蓝的谱系在芸苔属谱系的染色体加倍之前就已经分化（至少对于这条染色体而言）。甘蓝中的一些染色体片段似乎是三倍体，这表明需要重新评估关于芸苔属染色体通过加倍进化的经典模型。在拟南芥中，为约13%的所研究DNA探针定位的重复基因座分布表明，拟南芥中可能也发生过古老的重复事件。拟南芥和甘蓝之间的染色体分化程度似乎大于其他有比较图谱的同科物种。
