Meiotic segregation of the X and Y chromosomes and chromosome 1 analyzed by three-color FISH in human interphase spermatozoa.

Meiotic segregation of the X and Y chromosomes and chromosome 1 was analyzed by three-color fluorescence in situ hybridization (FISH) in 94,575 human interphase spermatozoa from four control subjects. More than 99% of the sperm cells were labeled. The proportions of X- and Y-bearing sperm were estimated to be 49.83% and 48.30%, respectively. The disomy rates were 0.04%, 0.009%, and 0.20% for the X and Y chromosomes and chromosome 1, respectively. Hyperhaploidy with an extra gonosome was found in 0.34% of spermatozoa, due to nondisjunction during meiosis I. The frequency of diploidy was 0.11% at meiosis I and 0.036% at meiosis II. Cohybridization of one autosomal and two gonosomal probes, in three-color FISH in interphase spermatozoa, seems to accurately discriminate diploidies from disomies, as well as the meiotic origin of gonosomal aneuploidies in sperm cells.