The origin and evolution of human ampliconic gene families and ampliconic structure
The origin and evolution of human ampliconic gene families and ampliconic structure
复制标题
DOI：
10.1101/gr.5734907
复制
发表时间：
2007-04-01
期刊：
影响因子：
7
通讯作者：
Takahata, Naoyuki
中科院分区：
文献类型：
--
作者：
Bhowmick, Bejon Kumar;Satta, Yoko;Takahata, Naoyuki
在人类Y染色体扩增子中的9个男性特异性基因家族中，我们研究了7个家族的起源和进化，其中配子体和正配子体序列是可用的。原始哺乳动物性染色体中的原始X/Y基因对在起源中起主要作用，并产生了五个基因家族：XKRY，VCY，HSFY，RBMY和TSPY。这些家系中配子体X-和Y-连锁拷贝之间的分歧时间与以前的X-染色体位置有很好的相关性。CDY和DAZ家族分别通过常染色体拷贝的逆转和转座而异常地起源，但CDY具有神秘起源的X连锁拷贝。我们还调查了Y连锁拷贝的基因家族的扩增位置（回文序列，反向重复序列和TSPY阵列）的光之间的进化相关性。虽然位于回文序列中相同臂位置的任何一对拷贝都是相同的，或者通过频繁的基因转换几乎相同，但位于不同臂位置的拷贝却截然不同。由于这些和其他不同的拷贝在不同的基因家族几乎同时扩增卡他鼻的干谱系，我们把这些同时扩增的证据精心形成的Y ampliconic结构。奇怪的是，位于不同回文区的基因家族中的一些拷贝表现出高度的序列相似性，并且在大多数情况下，这种相似性极大地延伸到包含这些拷贝的重复单元。似乎这样的回文重复单位已经整体进化，但它们在回文之间经历了频繁的交换。
Out of the nine male-specific gene families in the human Y chromosome amplicons, we investigate the origin and evolution of seven families for which gametologous and orthologous sequences are available. Proto-X/Y gene pairs in the original mammalian sex chromosomes played major roles in origins and gave rise to five gene families: XKRY, VCY, HSFY, RBMY, and TSPY. The divergence times between gametologous X- and Y-linked copies in these families are well correlated with the former X- chromosomal locations. The CDY and DAZ families originated exceptionally by retroposition and transposition of autosomal copies, respectively, but CDY possesses an X- linked copy of enigmatic origin. We also investigate the evolutionary relatedness among Y-linked copies of a gene family in light of their ampliconic locations ( palindromes, inverted repeats, and the TSPY array). Although any pair of copies located at the same arm positions within a palindrome is identical or nearly so by frequent gene conversion, copies located at different arm positions are distinctively different. Since these and other distinct copies in various gene families were amplified almost simultaneously in the stem lineage of Catarrhini, we take these simultaneous amplifications as evidence for the elaborate formation of Y ampliconic structure. Curiously, some copies in a gene family located at different palindromes exhibit high sequence similarity, and in most cases, such similarity greatly extends to repeat units that harbor these copies. It appears that such palindromic repeat units have evolved by and large en bloc, but they have undergone frequent exchanges between palindromes.