. The beginnings of embryonic development : A symposium organized by the Section on Zoological Sciences of the American Association for the Advancement of Science, cosponsored by the American Society of Zoologists and the Association of Southeastern Biologists, and presented at the Atlanta meeting, December 27, 1955. Embryology. 182 NUCLEOCYTOPLASMIC RELATIONS allele. Sometimes half the animal bilaterally is lemon lethal, and the other half wild type, each region being autonomous. At other times, certain portions of the body or head are lemon lethal with the rest wild type; or the inverse occu
. The beginnings of embryonic development : A symposium organized by the Section on Zoological Sciences of the American Association for the Advancement of Science, cosponsored by the American Society of Zoologists and the Association of Southeastern Biologists, and presented at the Atlanta meeting, December 27, 1955. Embryology. 182 NUCLEOCYTOPLASMIC RELATIONS allele. Sometimes half the animal bilaterally is lemon lethal, and the other half wild type, each region being autonomous. At other times, certain portions of the body or head are lemon lethal with the rest wild type; or the inverse occurs where only a small patch of wild-type tissue is present on the adult animal. The lethal effect of the gene is nonautonomous, and a male will eclose if only a small patch of wild-type tissue is present. The hereditary background necessary for production of the mosaics is not fully understood at present; not all females of the lemon lethal stock produce mosaics, but when one female is a mosaic producer she MOSAIC HAPLOID EMBRYO. TWO PRONUCLEI FROM BINUCLEATE OOCYTE (POSTULATED) TWO PRONUCLEI FROM UNINUCLEATE OOCYTE (ACTUAL) Fig. 6. Representation of normal meiosis, meiosis in a binucleate oocyte, and meiosis in which two meiotic products become pronuclei. tends to produce others. Gynandromorphs from virgins are rare, but they also occur. In any event, the occurrence of a haploid mosaic male means that the egg from which it originated was binucleate. In which sense is it binucleate—two oocyte nuclei undergoing meiosis side by side, or two meiotic products from one oocyte nucleus becoming cleavage nuclei (Fig. 6)? In a cytological investiga- tion of oocytes from females that produced mosaic males, no more than one nucleus was observed in any developing oocyte; however, in several cases, eggs were observed which were not blocked at the first meiotic metaphase. Meiosis was continuing. Please note that these images are extracted from scanned page images that may have been digital
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Keywords: ., bookcentury1900, bookpublisherwashington, booksubjectembryology
