Chromosome triplication found across the tribe Brassiceae
Chromosome triplication found across the tribe Brassiceae
复制标题
DOI：
10.1101/gr.3531105
复制
发表时间：
2005-04-01
期刊：
影响因子：
7
通讯作者：
Schubert, I
中科院分区：
文献类型：
--
作者：
Lysak, MA;Koch, MA;Schubert, I
我们已经使用了一个类似的8.7-Mb BAC重叠群的拟南芥4号染色体跟踪homeopathy染色体区域在21个物种的家庭拟南芥科。该片段的同源物可以在所有测试物种中鉴定。Calepina，Conringia和Ssymophilus种的粗线期染色体的绘画（2n = 14，16），传统上被置于拟南芥族，显示了拟南芥重叠群的一个同源拷贝，而该族的其余分类群（2n = 14-30）中发现了3个拷贝，其中3个芸苔属物种（2n = 34、36和38）和欧洲芥（2n = 30）有6个拷贝对应于8.7Mb片段。多个同源异型拷贝在结构上与拟南芥片段相对应，或者通过二倍体化基因组内的倒位和易位进行重排。这些染色体重排伴随着染色体融合/分裂，导致了今天的染色体数目变异在菊科。基于叶绿体5 '-trnL（UAA）-trnF（GAA）区域的系统发育关系和基于查耳酮合酶基因的序列数据估计的分歧时间与比较绘画数据一致，并将Calepina，Conringia和Ssymophylla置于具有三重基因组的植物科物种的分支之外。最有可能的是，含有三个或六个拷贝对的物种起源于一个共同的六倍体祖先，其基本基因组与拟南芥相似。推测的六倍化事件发生后，紫茎泽兰科分裂，7.9和14.6 Mya之间。
We have used an similar to 8.7-Mb BAC contig of Arabidopsis thaliana Chromosome 4 to trace homeologous chromosome regions in 21 species of the family Brassicaceae. Homeologs of this segment could be identified in all tested species. Painting of pachytene chromosomes of Calepina, Conringia, and Sisymbrium species (2n = 14, 16), traditionally placed in tribe Brassiceae, showed one homeologous copy of the Arabidopsis contig, while the remaining taxa of the tribe (2n = 14-30) revealed three, and three Brassica species (2n = 34, 36, and 38) and Erucastrum gallicum (2n = 30) had six copies corresponding to the 8.7-Mb segment. The multiple homeologous copies corresponded structurally to the Arabidopsis segment or were rearranged by inversions and translocations within the diploidized genomes. These chromosome rearrangements accompanied by chromosome fusions/fissions led to the present-day chromosome number variation within the Brassiceae. Phylogenetic relationships based on the chloroplast 5'-trnL (UAA)-trnF(GAA) region and estimated divergence times based on sequence data of the chalcone synthase gene are congruent with comparative painting data and place Calepina, Conringia, and Sisymbrium outside the clade of Brassiceae species with triplicated genomes. Most likely, species containing three or six copy pairs descended from a common hexaploid ancestor with basic genomes similar to that of Arabidopsis. The presumed hexaploidization event occurred after the Arabidopsis-Brassiceae split, between 7.9 and 14.6 Mya.