The objective of this study is to elucidate the mechanism by which the Y chromosome determines sexual phenotype. To this end, we have devised a novel method for specifically cloning Ychromosome DNA and have constructed a library that is sufficiently large to contain the entire complement of Y chromosome DNA sequences. This library will be used to analyze Y encoded nRNAs in developing embryos. This class of study has the potential to identify transcribed genes on the Y chromosome which initiate the developmental pathway of sexual differentiation. Using this library of cloned Y DNA we will also study the conservation and drift of DNA sequences on the Y chromosome during 200 million years of vertebrate evolution. Many children suffering from developmental disorders of sexual differentiation carry genetic anomalies involving the Y chromosome. Cloned Y chromosome DNA will be used to establish the relationship between chromosome anomalies, gene expression and abnormal patterns of sexual differentiation in man.
