SOME EFFECTS OF GENOTYPE AND COMPOSITION OF THE CULTURE-MEDIUM ON THEDEVELOPMENT OF MOUSE ZYGOTES IN-VITRO

The effects of EDTA and the presence of glucose and glutamine in CZB m edium on the development of mouse zygotes of different genotype were i nvestigated. Although 30-80% of zygotes (depending on the cross) passe d the 2-cell stage in EDTA-free medium, the addition of a low concentr ation of EDTA was necessary in these experiments to obtain blastocysts in culture. In reciprocal crosses between outbred (Qs), inbred (DBA/2 ) and hybrid (B10D2F(1)) stock, there was evidence of a strong influen ce of the maternal genome on zygote development, with those from B10D2 F(1) females performing best irrespective of sire. A paternal influenc e on development was also evident but the most successful sire varied with the genotype of female used and reciprocal crosses differed great ly in the ability of the resultant zygote to develop in culture. For z ygotes recovered from Qs females, CZB medium containing glucose and gl utamine supported development to the blastocyst stage better than did medium devoid of these substrate. Tests with embryos from B10D2F(1) fe males indicated that the presence of glucose for the whole or for part of the incubation period stimulated blastocyst development. However, the addition of glutamine to the medium in these tests had no signific ant effect on the development of blastocysts.