PARTIAL DELETION OF THE Y-CHROMOSOME REMOVES THE EFFECT OF PATERNAL GENOME IMPRINTING ON PERIOVUM SENSITIVITY TO HYALURONIDASE IN MICE

Cumulus-oocyte complexes from the two consomic strains of mice, B10.BR and B10.BR-Ydel (with a partial deletion of the Y chromosome) and the BALB/c strain, as well as reciprocal F1 and F2 hybrids, were tested f or their susceptibility to attack by hyaluronidase. The cumulus cell d ispersal was significantly more rapid in the eggs of B10.BR females an d of F1 and F2 hybrid females sired by the B10.BR males than in those of BALB/c females and hybrids sired by BALB/c males. These results con firm the earlier data of Bander et al. (1989) which were interpreted a s evidence of paternal imprinting of the C57BL genome. In contrast, cu mulus cell dispersal in the eggs of females sired by B10.BR-Ydel males was significantly slower than in females sired by B10.BR males, and d id not differ from that in the BALB/c strain. The results suggest that the partial deletion of the Y chromosome abolished the effect of pate rnal genome imprinting which is observed in the B10.BR strain.