An exon map of the AZFc male infertility region of the human Y Chromosome

STS markers spanning the AZFc region of human Y Chromosome (Chr) were used to isolate a series of 14 P1 artificial chromosome (PAC) clones covering at least 560 kb of DNA. End clone analysis of these PAC clones was used to de rive 10 new STS markers. Together with other markers mapped to the region, an STS content analysis was used to assemble these PAC clones into three di stinct contigs. A minimum tiling path of ten PAC clones was subjected to ex on trapping to identify potentially new genes mapping to the AZFs region. I n all, 39 potential exons were isolated, including 2 exons from the DAZ gen e, 3 exons from the BPY2 gene, 2 exons from the PRY gene, and 1 exon from a member of the RBM II gene family; all these genes have been shown previous ly to map to the AZFc region. One further exon was found that shows homolog y to the DFFRY gene, which maps to Yq11.2, indicating that there may be a f urther copy of this gene or a pseudogene in the distal Yq euchromatin. The majority of the remaining potential exons appear to be novel, suggesting th at additional genes lie in the AZFc region. Mapping of these exons by PCR a nalysis of somatic cell hybrids has shown that six of these exons are homol ogous to autosomal sequences, and five to sequences on the X Chr. RT-PCR an alysis of primary cDNA from adult testis, brain, liver, and skeletal muscle mRNA has shown that II of the novel exons are expressed in one or a combin ation of these tissues, indicating that they form parts of genuine transcri pts.