MOLECULAR ANALYSIS OF THE GENOMIC STRUCTURE OF THE HUMAN Y-CHROMOSOMEIN THE EUCHROMATIC PART OF ITS LONG ARM (YQ11)

Conventional methods of long range restriction mapping for analysis of the genomic DNA structure failed in Yq11, because single-copy DNA pro bes for blot hybridization analyses are rare and the rate of DNA methy lation is high in this Y region. Numerous repetitive sequence blocks o f unknown extensions are scattered throughout Yq11 and a patchwork of X-Y homologous DNA blocks were found by different investigators. There fore, our approach towards a molecular analysis of this Y region reduc ed this complexity by performing first its molecular analysis in YAC c lones mapping to Yq11. YACs contain only a part of the whole Yq11 DNA structure. In this paper, we present our first results of this approac h based on quantitative blot analysis of 51 DNA loci in 67 YAC clones. The YACs were isolated from the three CEPH libraries and mapped to a contig of 13 Mb from proximal to distal Yq11 with aid of a detailed in terval map. In distal Yq11, our analysis revealed the presence of loca l amplification events of different DNA domains. A model of their poss ible arrangement is presented.