A PCR product derived from female DNA with regional localization on the Y chromosome

A 154-bp PCR product amplified from human female DNA mapped onto the Y chro mosome under high- stringency in situ hybridization conditions. The female DNA sequence revealed an 89% homology with the HSDYZ1 sequence. When the sa me primers were used to amplify male DNA, a 154-bp DNA fragment was also ob tained, showing a 98% homology with HSDYZ1. However, although the HSDYZ1 se quence is widely distributed along the long arm of the Y chromosome, both o f these particular PCR products are di-regionally localized within this dis tal block of constitutive heterochromatin. In situ hybridization under lowe r stringency showed that these 154-bp sequences map both onto the autosomes and the Y chromosome. Overall, this paper shows (i) a new class of DNA seq uences shared by the autosomes and the Y chromosome; and (ii) a substructur ed organization of some DNA repeats within the DYZ1 family that forms a lar ge part of the constitutive heterochromatin of the Y chromosome.