The number of cells and cleavages in haploid, diploid, polyploid, and other heteroploid mouse embryos at 3½ days gestation
✍ Scribed by Edwards, R. G.
- Publisher
- John Wiley and Sons
- Year
- 1958
- Tongue
- English
- Weight
- 937 KB
- Volume
- 138
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Much evidence has recently accumulated on the induction of various kinds of heteroploidy in mouse embryos. Haploid, triploid, tetraploid and other heteroploid embryos have been found after the second meiotic or first cleavage divisions were suppressed by heat (Fischberg and Beatty, '5'2a; Beatty and Fischberg, '52), by colchicine (Edwards, '58b and c) or spontaneously without any treatment (Beatty and Fischberg, '51a ; Fischberg and Beatty, '52b). Gynogenetic haploids and other heteroploids have been recovered after various treatments on spermatozoa before fertilization which were designed to induce gynogenesis (Edwards, '57a and b, '58a). I n all of these experiments, the number of nuclei was counted in the 3X-day-old embryos in addition to their chromosome number. The purpose of the present paper is to analyze the development of each type of heteroploid embryo in terms of the number of nuclei o r the number of cleavages, and to compare the development of heteroploid embryos with that of diploids. Beatty and Fischberg ('51b) have analyzed the cell number of many triploid and tetraploid mouse embryos, and they concluded that the mean number of cells in polyploid embryos relative to diploids was approximately in inverse proportion to the number of chromosome sets present in the embryos.