Mechanisms of chromosome number reduction in Arabidopsis thaliana and related Brassicaceae species
Mechanisms of chromosome number reduction in Arabidopsis thaliana and related Brassicaceae species
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DOI：
10.1073/pnas.0510791103
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发表时间：
2006-03-28
影响因子：
11.1
通讯作者：
Schubert, I
中科院分区：
文献类型：
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作者：
Lysak, MA;Berr, A;Schubert, I
染色体互补物的进化可以通过基因组测序、比较遗传作图和比较染色体彩绘来解决。以前，遗传图谱和基于基因的染色体组学的比较表明，拟南芥（n = 5）和具有6或7对染色体的相关物种的核型来自具有8对染色体的祖先核型。为了验证这一假设，我们使用A. thaliana的遗传图谱按照拟南芥（Arabidopsis lyrata）和红铃兰（Capsella rubella）的遗传图谱排列（均n = 8），A. thaliana，A. lyrata、Neslia paniculata、Turningglabra和Hornungia alpina。这种方法使我们能够绘制A。lyrata着丝粒作为一个先决条件，以确定一个假定的祖先核型（n = 8），并阐明进化机制，形成核型的A. Thaliana及其亲属。我们的结论是，染色体“融合”在A。thaliana是由（i）臂间倒位产生的端着丝粒染色体，（ii）两条染色体（一条或两条端着丝粒染色体）之间的相互易位，和（iii）消除了除了“融合染色体”之外出现的微小染色体。“比较染色体绘画应用于N. paniculata（n = 7）、T. glabra（n = 6）和H.高山族（n = 6），其遗传图谱不可用，揭示了所有测试物种之间的染色体共线性，并允许我们从假定的祖先核型（n = 8）重建其染色体的进化。虽然涉及不同的祖先染色体，染色体数目减少遵循类似的路线内发现拟南芥属。
Evolution of chromosome complements can be resolved by genome sequencing, comparative genetic mapping, and comparative chromosome painting. Previously, comparison of genetic maps and gene-based phylogenies suggested that the karyotypes of Arabidopsis thaliana (n = 5) and of related species with six or seven chromosome pairs were derived from an ancestral karyotype with eight chromosome pairs. To test this hypothesis, we applied multicolor chromosome painting using contiguous bacterial artificial chromosome pools of A. thaliana arranged according to the genetic maps of Arabidopsis lyrata and Capsella rubella (both n = 8) to A. thaliana, A. lyrata, Neslia paniculata, Turritis glabra, and Hornungia alpina. This approach allowed us to map the A. lyrata centromeres as a prerequisite to defining a putative ancestral karyotype (n = 8) and to elucidate the evolutionary mechanisms that shaped the karyotype of A. thaliana and its relatives. We conclude that chromosome "fusions" in A. thaliana resulted from (i) generation of acrocentric chromosomes by pericentric inversions, (ii) reciprocal translocation between two chromosomes (one or both acrocentric), and (iiii) elimination of a minichromosome that arose in addition to the "fusion chromosome." Comparative chromosome painting applied to N. paniculata (n = 7), T. glabra (n = 6), and H. alpina (n = 6), for which genetic maps are not available, revealed chromosomal colinearity between all species tested and allowed us to reconstruct the evolution of their chromosomes from a putative ancestral karyotype (n = 8). Although involving different ancestral chromosomes, chromosome number reduction followed similar routes as found within the genus Arabidopsis.