Low X/Y divergence in four pairs of papaya sex-linked genes
Low X/Y divergence in four pairs of papaya sex-linked genes
复制标题
DOI：
10.1111/j.1365-313x.2007.03329.x
复制
发表时间：
2008-01-01
期刊：
影响因子：
7.2
通讯作者：
Ming, Ray
中科院分区：
文献类型：
--
作者：
Yu, Qingyi;Hou, Shaobin;Ming, Ray
开花植物的性染色体与动物的性染色体相比，进化得相对较晚，只有少数是异型的。木瓜同态性染色体表现出早期性染色体进化的特征。我们研究了配对的X和y特异性细菌人工染色体（BACs）的特征，并估计了四对性别连锁基因的分化时间。我们报告了X和雌雄同体Y （Y-h）染色体之间长连续基因组DNA序列的比较分析结果。在Y染色体男性特异性区域（MSY）检测到大量的染色体重排，包括倒位、缺失、插入、重复和易位，显示了MSY在重组停止后的动态进化过程。在MSY的两个区域记录了DNA序列扩增，表明细胞学上同态的性染色体在分子水平上是异态的。对四个X和Y-h基因对序列差异的分析得出了估计的差异年龄在50万年到220万年之间，支持了木瓜性染色体最近起源的说法。本研究结果表明，性染色体并不是在加勒比科的科系水平上进化的，并进一步证实了性染色体在某些世系的种水平上进化的理论。
Sex chromosomes in flowering plants, in contrast to those in animals, evolved relatively recently and only a few are heteromorphic. The homomorphic sex chromosomes of papaya show features of incipient sex chromosome evolution. We investigated the features of paired X- and Y-specific bacterial artificial chromosomes (BACs), and estimated the time of divergence in four pairs of sex-linked genes. We report the results of a comparative analysis of long contiguous genomic DNA sequences between the X and hermaphrodite Y (Y-h) chromosomes. Numerous chromosomal rearrangements were detected in the male-specific region of the Y chromosome (MSY), including inversions, deletions, insertions, duplications and translocations, showing the dynamic evolutionary process on the MSY after recombination ceased. DNA sequence expansion was documented in the two regions of the MSY, demonstrating that the cytologically homomorphic sex chromosomes are heteromorphic at the molecular level. Analysis of sequence divergence between four X and Y-h gene pairs resulted in a estimated age of divergence of between 0.5 and 2.2 million years, supporting a recent origin of the papaya sex chromosomes. Our findings indicate that sex chromosomes did not evolve at the family level in Caricaceae, and reinforce the theory that sex chromosomes evolve at the species level in some lineages.