A technique to examine cock sperm chromosomes using zona-free hamster eggs

For the first time the visualization of cock sperm chromosomes using zona-free hamster eggs was described. Different variants of egg treatment were tested: varying the duration of incubation of eggs with spermatozoa from 5-6 to 20 h and the cytostatic treatment (colchicine) from 35 min to 9 h, varying the concentration of colchicine from 0.4-400 micrograms/ml and the hypotonic treatment with 0.1% and/or 1.0% sodium citrate or with distilled water from 2-5 to 12 min. In all variants sperm penetration was found, with changes in the head of sperm and the formation of pronucleus but there was no breakdown of the pronuclear envelopes. Only experiments, in which eggs were incubated without colchicine, were successful.