Type | MGI:General | Description | all heterozygous oocytes show significantly reduced ability to extrude the first polar body; oocytes from wild-type female mice born to heterozygous mothers show significantly reduced ability to extrude the first polar body relative to oocytes from wild-type females born to wild-type mothers regardless of their genotype (wild-type or heterozygous), most E13.5 embryos (7/8) produced by heterozygous matings are smaller than embryos produced by wild-type matings |