The presence of Alu family repeats is closely associated with interspecies length polymorphisms of certain genomic regions among different higher primates. By sequence analysis of cloned DNA, we show that one major cause for the length difference between the gibbon adult α-globin locus and those of human, orangutan, and Old World monkeys is the existence of multimeric Alu family repeats. Triplet Alu family repeats exist at two genomic sites of gibbon. Instead, singleton or doublet Alu family repeats are present at the orthologous positions in other higher primates. Sequence comparisons suggest that these doublet and triplet Alu repeats have been created by successive insertion of different singleton Alu repeat sequences, of ≈300 bp, into the same genomic spot(s) during primate evolution. The approximate dates of insertion of these singleton Alu repeats support the concept of overlapping periods of active transposition or retroposition of Alu repeat subfamilies. This dynamic flow of Alu repeat sequences during primate evolution into the adult α-globin loci, but not β-globin-like loci, is consistent with the previous finding that R-banding regions of the primate chromosomes are enriched in Alu repeats.
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - Aug 1 1993|
- Hot spots of insertion
- α-globin locus
ASJC Scopus subject areas