COMPARISON OF THE NUCLEAR-DNA STABILITY AGAINST FREEZING-THAWING AND HIGH-TEMPERATURE TREATMENTS BETWEEN SPERMATOZOA AND SOMATIC-CELLS

Thermostability of sperm genome against freezing-thawing and high temp erature treatments was assessed by comparing the degradation patterns of genomic DNAs from epididymal sperms and somatic tissues. Golden ham ster liver, kidney, epididymal sperm, and testis were frozen and thawe d repeatedly, or incubated in a hot water bath. Genomic DNAs were isol ated and then separated by agarose gel electrophoresis. It was reveale d that the size of sperm genomic DNA was hardly changed after freezing -thawing treatment, however, the DNA sizes of the other three tissues were gradually reduced with an increasing number of freezing-thawing c ycles. In contrast, high temperature treatment appears to damage not o nly the genomic DNAs of somatic cells but also those of spermatozoa.