Evolution by the birth-and-death process in multigene families of the vertebrate immune system
Evolution by the birth-and-death process in multigene families of the vertebrate immune system
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DOI：
10.1073/pnas.94.15.7799
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发表时间：
1997-07-22
影响因子：
11.1
通讯作者：
Sitnikova, T
中科院分区：
文献类型：
--
作者：
Nei, M;Gu, X;Sitnikova, T
协调进化经常被用来解释主要组织相容性复合体（MHC）基因和免疫球蛋白（IG）基因的多基因家族的多样性和进化，然而，这一假说一直存在争议，因为来自同一物种的这些家族的成员基因彼此之间的关系不一定比来自不同物种的基因之间的关系更密切。我们对MHC和IG系统的几个多基因家族进行了系统发育分析。结果表明，这些家系的进化模式与协同进化模式有很大的不同，但符合出生-死亡的进化模式，即重复基因复制产生新基因，某些重复基因在基因组中保持较长时间，而另一些重复基因则被删除或因有害突变而失去功能。我们发现很少有证据表明基因座间的基因转换在MHC和IG多基因家族的进化中起重要作用。
Concerted evolution is often invoked to explain the diversity and evolution of the multigene families of major histocompatibility complex (MHC) genes and immunoglobulin (Ig) genes, However, this hypothesis has been controversial because the member genes of these families from the same species are not necessarily more closely related to one another than to the genes from different species, To resolve this controversy, we conducted phylogenetic analyses of several multigene families of the MHC and Ig systems. The results show that the evolutionary pattern of these families is quite different from that of concerted evolution but is in agreement with the birth-and-death model of evolution in which new genes are created by repeated gene duplication and some duplicate genes are maintained in the genome for a long time but others are deleted or become nonfunctional by deleterious mutations. We found little evidence that interlocus gene conversion plays an important role in the evolution of MHC and Ig multigene families.