Male infertility, genetic analysis of the DAZ genes on the human Y chromosome and genetic analysis of DNA repair

Many genes that are required for fertility have been identified in model organisms (Castrillon et al., 1993; Chubb et al., 1993; Mello et al., 1996). Mutations in these genes cause infertility due to defects in development of the germ cell lineage, but the organism is otherwise healthy. Although human reproduction is undoubtedly as complex as that of other organisms, very few fertility loci have been mapped (Reijo et al., 1995; Vogt et al., 1996; Aittomaki et al., 1995). This is in spite of the prevalence of human infertility, the lack of effective treatments to remedy germ cell defects, and the cost to couples and society of assisted reproductive techniques. Fifteen percent of couples are infertile and half of all cases can be traced to the male partner. Aside from defects in sperm production, most infertile men are otherwise healthy. This review is divided into two distinct parts to discuss work that: (i) led to the identification of several genes on the Y chromosome that likely function in sperm production; and (ii) implicates DNA repair in male infertility via increased frequency of mutations in DNA from men with meiotic arrest. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.