TSPY-related sequences represent a microheterogeneous gene family organized as constitutive elements in DYZ5 tandem repeat units on the human Y chromosome.

TSPY (testis-specific protein, Y-encoded) is encoded by members of a Y-chromosome-specific sequence family. We show here that TSPY elements are part of the DYZ5 repeat unit. We have established a cosmid library of Y-chromosomal DNA derived from the hybrid cell line 3E7 and isolated eight cosmids representing 15 TSPY elements. Interindividual variability with respect to TSPY copy number was observed. One cosmid clone was investigated in detail by subcloning and sequencing. Sequence microheterogeneity was identified among both transcribed and nontranscribed TSPY elements. Transcript variability is not restricted to single basepair exchanges. We present data for the existence of at least three differently sized TSPY transcripts, caused by different patterns of splicing.