Assum G, Gartmann C, Schempp W, Wöhr G
Abteilung Humangenetik der Universität, Ulm, Federal Republic of Germany.
Genomics. 1994 May 1;21(1):34-41. doi: 10.1006/geno.1994.1221.
Approximately 50 members of the primate-specific multisequence family chAB4 are located as clusters at eight different chromosomal loci within the human genome. The whole cloned region of chAB4 represents a single-copy or low-copy sequence in all nonhuman primates tested, with the exception of the chimpanzee, for which we found chAB4 copy numbers similar to those in the human. An Alu element was inserted into chAB4 after the divergence of the Old World monkeys from the hominoids but before chAB4 was amplified. The first amplification step could be dated after the great apes and the human diverged from the Old World monkeys. We have evidence that neither the copy numbers nor the chromosomal locations remained stable after this initial step and that gross alterations in the relative copy numbers of individual family members occurred even after the divergence of the human and the chimpanzee. Taken together, our data suggest that chAB4, in an evolutionary sense, is an unusually unstable sequence family.
灵长类特有的多序列家族chAB4的大约50个成员在人类基因组内的8个不同染色体位点上成簇分布。在所有测试的非人类灵长类动物中，chAB4的整个克隆区域代表单拷贝或低拷贝序列，但黑猩猩除外，我们发现黑猩猩的chAB4拷贝数与人类相似。在旧世界猴与人科动物分化之后，但在chAB4扩增之前，一个Alu元件插入到了chAB4中。第一次扩增步骤可以追溯到大猿和人类与旧世界猴分化之后。我们有证据表明，在这第一步之后，拷贝数和染色体位置都没有保持稳定，而且即使在人类和黑猩猩分化之后，单个家族成员的相对拷贝数也发生了重大变化。综上所述，我们的数据表明，从进化意义上讲，chAB4是一个异常不稳定的序列家族。
