HIGH-RESOLUTION CARTOGRAPHY OF RECENTLY INTEGRATED HUMAN-CHROMOSOME 19-SPECIFIC ALU FOSSILS

The recently inserted subfamilies of Alu retroposons (Ya5/8 and Yb8) a re composed of approximately 2000 elements. We have screened a human c hromosome 19-specific cosmid library for the presence of Ya5/8 and Yb8 Alu family members. This analysis resulted in the identification of 1 2 Ya5/8 Alu family members and 15 Yb8 Alu family members from human ch romosome 19. The total number of Ya5/8 and Yb8 Alu family members loca ted on human chromosome 19 does not differ from that expected based up on random integration of Alu repeats within the human genome. The dist ribution of both subfamilies of Alu elements along human chromosome 19 also appears to be random. DNA sequence analysis of the individual Al u elements revealed a low level of random mutations within both subfam ilies of Alu elements consistent with their recent evolutionary origin . Oligonucleotide primers complementary to the flanking unique sequenc es adjacent to each Alu element were used in polymerase chain reaction assays to determine the phylogenetic distribution and human genomic v ariation associated with each Alu family member. All of the chromosome 19-specific Ya5/8 and Yb8 Alu family members were restricted to the h uman genome and absent from orthologous positions within the genomes o f several non-human primates. Three of the Yb8 Alu family members were polymorphic for insertion presence/absence within the genomes of a di verse array of human populations. The polymorphic Alu elements will be useful tools for the study of human population genetics. (C) 1998 Aca demic Press.