Philipsen J N, de Vries J E, Samallo J, van Dijk C, Arnberg A C, AB G
Laboratory of Biochemistry, Groningen, The Netherlands.
J Mol Evol. 1989 Mar;28(3):185-90. doi: 10.1007/BF02102475.
An allele giving rise to a polymorphism within the 3' part of the chicken vitellogenin gene was cloned, sequenced, and compared to the previously cloned allele. The polymorphism is formed by a perfect copy of 343 bp from intron 32 in tandem array with a perfect copy of 244 bp from intron 33; this 587-bp element is inserted in a head-to-tail arrangement in intron 33. We propose a mechanism in which an unequal crossing-over resulted in a vitellogenin gene with two exons 33, one of which was subsequently deleted. Thus, intron 33 was enlarged by the tandem repeats without affecting the protein-encoding sequence of the gene. At the boundaries of the repeated elements, two short direct repeats are found that resemble the recombination signals of immunoglobulin genes. They may have had a key role in the formation of the new allele.
克隆了一个导致鸡卵黄蛋白原基因3'端出现多态性的等位基因，对其进行测序并与先前克隆的等位基因进行比较。该多态性由来自第32内含子的343 bp的完美拷贝与来自第33内含子的244 bp的完美拷贝串联排列形成；这个587 bp的元件以头对头的方式插入到第33内含子中。我们提出了一种机制，即不等交换导致了一个含有两个第33外显子的卵黄蛋白原基因，其中一个随后被删除。因此，第33内含子因串联重复而扩大，而不影响该基因的蛋白质编码序列。在重复元件的边界处，发现了两个短的直接重复序列，它们类似于免疫球蛋白基因的重组信号。它们可能在新等位基因的形成中起了关键作用。
