Intrachromosomal rearrangements in avian genome evolution: evidence for regions prone to breakpoints

It is generally believed that the organization of avian genomes remains highly conserved in evolution as chromosome number is constant and comparative chromosome painting demonstrated there to be very few interchromosomal rearrangements. The recent sequencing of the zebra finch (Taeniopygia guttata) genome allowed an assessment of the number of intra-chromosomal rearrangements between it and the chicken (Gallus gallus) genome, revealing a surprisingly high number of intra-chromosomal rearrangements. With the publication of the turkey (Meleagris gallopavo) genome it has become possible to describe intrachromosomal rearrangements between these three important avian species, gain insight into the direction of evolutionary change and assess whether breakpoint regions are reused in birds. To this end, we aligned entire chromosomes between chicken, turkey and zebra finch, identifying syntenic blocks of at least 250kb. Potential optimal pathways of rearrangements between each of the three geno...学界普遍认为，鸟类基因组的组织在进化过程中高度保守——其染色体数目恒定，且通过比较染色体涂染（comparative chromosome painting）技术证实，鸟类基因组内的染色体间重排事件极少。近期完成的斑胸草雀（Taeniopygia guttata）基因组测序，使得研究者得以评估其与鸡（Gallus gallus）基因组之间的染色体内重排数目，结果却揭示出数量惊人的染色体内重排事件。随着火鸡（Meleagris gallopavo）基因组测序结果的发表，研究者得以描述这三种重要鸟类物种之间的染色体内重排情况，深入解析进化改变的方向，并探究鸟类基因组的断裂点区域是否存在重复使用现象。为此，我们对鸡、火鸡与斑胸草雀的全染色体进行了序列比对，鉴定出至少250kb的同线性区块（syntenic blocks）。针对这三个物种两两之间的重排潜在最优通路，[原文内容未完整给出]