Evolution and structure of the fibrinogen genes. Random insertion of introns or selective loss?
Evolution and structure of the fibrinogen genes. Random insertion of introns or selective loss?
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纤维蛋白原基因的进化和结构。
DOI：
10.1016/0022-2836(85)90179-2
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发表时间：
1985
影响因子：
5.6
通讯作者：
Kant,JA
中科院分区：
文献类型：
--
作者：
Crabtree,GR;Comeau,CM;Fowlkes,DM;FornaceJr,AJ;Malley,JD;Kant,JA
染色体连锁以及序列同源性提供了明确的证据，即纤维蛋白原的α、β和γ链的基因是由单个祖先基因的连续复制产生的。然而，当通过氨基酸同源性比对三条纤维蛋白原链时，对于所有三条链，间插序列的位置仅在两个位置处重合。虽然一个额外的内含子出现在β和γ链中的同源位点，但三个基因中其余11个内含子的位置都不共享。在三个纤维蛋白原基因中内含子的这种排列表明，要么内含子被选择性地丢失，这意味着在保留的内含子中存在必要的信息，要么共同的内含子存在于祖先纤维蛋白原基因中，并且内含子自原始基因的三倍化以来被随机插入。选择性丢失内含子的可能性更大，这意味着大约10亿年前存在的祖先基因一定是由许多小外显子组成的。
Chromosomal linkage as well as sequence homologies provide unequivocal evidence that the genes for the alpha, beta and gamma chains of fibrinogen arose by successive duplication of a single ancestral gene. Yet, when the three fibrinogen chains are aligned by amino acid homology, the positions of intervening sequences coincide at only two positions for all three chains. While one additional intron occurs at a homologous site in the beta and gamma chains, none of the positions of the remaining 11 introns in the three genes is shared. This arrangement of introns in the three fibrinogen genes suggests that either introns were selectively lost, implying that there is essential information in the retained introns, or the common introns were present in the ancestral fibrinogen gene and introns have been randomly inserted since the triplication of the original gene. The more likely possibility of selective loss of introns implies that the ancestral gene, as it existed about one billion years ago, must have been composed of numerous small exons.