"Cytogenetic" studies of spermatids of mice carrying Cattanach's translocation by flow cytometry

The DNA content of spermatids of mice carrying Cattanach's translocation has been measured with high precision by flow cytometry. The observation that the two peaks of DNA content in the haploid region of the DNA histograms represent X- and Y-bearing spermatids was tested and confirmed. Using flow cytometry, the difference in DNA content between the X and Y chromosomes in these mice was measured to be 5.2 +/- 0.1% of the total haploid genome as compared to 3.4 +/- 0.1% in normal mice. These results demonstrated the precision of flow cytometry for cytogenetic studies. Additional information on spermatogenesis in mice bearing Cattanach's translocation was obtained and showed a gradual loss of cells during spermatogenesis in those bearing the balanced form of the translocation.