THE Y-CHROMOSOME AND REPRODUCTIVE DISORDERS

Over the past decade the tools of modern molecular biology have provid ed unique insights into our fundamental understanding of developmental systems. These insights have been gleaned from the study of a wide va riety of model organisms including yeast (Saccharomyces cerevisiae), f ly (Drosophila), worm (Caenorhabditis elegans), and mouse. in man, the first analysis of developmental systems started with sexual different iation and focused on the role of Y-linked genes. The presence of livi ng developmental mutants in man affecting sexual development and the e arly technology of deletion mapping facilitated the isolation and iden tification of small segments of putative DNA suspected to contain sex- determining genes. The isolation of genes such as SRY (Sex Related gen e on Y) has provided the first insights into the molecular biology of human sexual differentiation. The focus on the Y chromosome has brough t further insights into chromosomal pairing, statural determinants in man, oncogenesis, spermatogenesis, haploid genomes, and the lineage of man himself. This paper provides the circumstantial and direct eviden ce to illustrate the importance of the Y chromosome in reproductive di sorders, and in the analysis of haploid genomes.