A young Alu subfamily amplified independently in human and African great apes lineages.
A young Alu subfamily amplified independently in human and African great apes lineages.
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一个年轻的 Alu 亚科在人类和非洲类人猿谱系中独立扩增。
作者：
E. Ziętkiewicz;C. Richer;W. Makałowski;J. Jurka;D. Labuda
不同进化时期灵长类基因组中Alu亚家族的多样性。Alu Sb 2属于一组年轻的亚家族，在位置65/66处具有特征性的两个核苷酸缺失。它由具有涉及位置246至252的序列片段的7个核苷酸重复的重复序列组成。在120个人类DNA样品中的5个基因组位点以及高等灵长类动物的DNA中检查了Sb 2插入物的存在。在四个人类基因座上缺乏插入多态性，而在猿类中没有orthopathic插入物，这表明所研究的重复序列在人类谱系的早期就发生了逆转，但在大猿的分歧之后。另一方面，类似的第五个位点（丁酰胆碱酯酶基因）的分析表明，当代这个亚家族的retropositional活动。通过半定量PCR，使用特异于Sb 2重复序列的引物对，我们估计它们的拷贝数约为1500个/人类单倍体基因组;黑猩猩和大猩猩中的相应数量低两个数量级，而在猩猩和猩猩中几乎检测不到Sb 2 Alu的存在。从人类和非洲大猿的PCR扩增的Sb 2重复序列的序列分析是一致的，在该模型中，Sb 2亚家族变异的成立独立地发生在黑猩猩，大猩猩和人类血统。
A variety of Alu subfamilies amplified in primate genomes at different evolutionary time periods. Alu Sb2 belongs to a group of young subfamilies with a characteristic two-nucleotide deletion at positions 65/66. It consists of repeats having a 7-nucleotide duplication of a sequence segment involving positions 246 through 252. The presence of Sb2 inserts was examined in five genomic loci in 120 human DNA samples as well as in DNAs of higher primates. The lack of the insertional polymorphism seen at four human loci and the absence of orthologous inserts in apes indicated that the examined repeats retroposed early in the human lineage, but following the divergence of great apes. On the other hand, similar analysis of the fifth locus (butyrylcholinesterase gene) suggested contemporary retropositional activity of this subfamily. By a semi-quantitative PCR, using a primer pair specific for Sb2 repeats, we estimated their copy number at about 1500 per human haploid genome; the corresponding numbers in chimpanzee and gorilla were two orders of magnitude lower, while in orangutan and gibbon the presence of Sb2 Alu was hardly detectable. Sequence analysis of PCR-amplified Sb2 repeats from human and African great apes is consistent with the model in which the founding of Sb2 subfamily variants occurred independently in chimpanzee, gorilla and human lineages.