In vivo, embryos which are homozygous for the t6 mutation die during egg cylinder development (gestation days 5·5-6·5). In vitro, these mutant embryos can be distinguished from their wild-type littermates by their developmental arrest and by the failure of their tropho-blast cells to transform to giant cells. We have investigated the nature of this lethality by constructing triploid embryos with varying combinations of the t6 mutant chromosome* The phenotypes of outgrowths from these triploid embryos were examined and compared with the phenotypes of outgrowths from 4-/ +, + /t6, and tft6 embryos. The data show 1) that + / t6/ t6 embryos are phenotypically wild-type, while t6/ t6/t6 embryos are phenotypically mutant and 2) that t6/t6/t6 and t6/ t6 embryos are developmentally arrested at the same stage of outgrowth.

You do not currently have access to this content.