Population heterogeneity in human sperm DNA content.
The range of variability in the population distribution characteristics of sperm DNA content was surveyed in a selected group of donors. The donors included identical twins, carriers of chromosomal translocations, and oligospermics. The DNA content of sperm was measured individually in an automated cytofluorometer. In contrast to normal donors with high sperm counts and relatively constant modal values of sperm DNA, the balanced carriers of translocations were oligospermic and showed wide dispersion of modal values. This is an unexpected finding, since reciprocal events in the alternate form of segregation, which occurs predominantly in male carriers of balanced translocations, should not alter modal values of sperm DNA nor should they be associated with oligospermia. It appears that sperm DNA content in oligospermia, independent of its association with translocation, varies over a wide range. Thus, it is likely that genetic factor(s) unrelated to chromosome translocation control sperm DNA content.