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The formation of the sex glands and germ cells of mammals I. The origin of the germ cells in the albino rat
Author(s) -
Hargitt Geo. T.
Publication year - 1925
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1050400305
Subject(s) - biology , gonadal ridge , germ line development , gonad , germ , mesenchyme , germinal epithelium , epithelium , germ plasm , germ cell , anatomy , coelom , embryo , microbiology and biotechnology , peritoneum , endocrinology , embryogenesis , spermatogenesis , genetics , gene
An early segregation of germ cells and migration through a germ track into the gonad does not occur in the albino rat. The germ cells are produced only from the peritoneum of the genital region and their earliest formation is coincident with the thickening of the coelomic epithelium to form the genital ridge. This takes place eleven days after insemination in embryos of approximately 18 somites. Germ cells continue to form from the peritoneum during the early development of the gonad. The peritoneum of this region also produces mesenchyme, smaller cells of the gonads, and the germinal epithelium. The argument for the specific character of the germ cells in vertebrates and their continuity from the egg is based largely upon assumption, and not upon substantial observations, and must be discarded. Germ‐cell origin is a problem of cellular differentiatio, and not of early segregation.