The Booroola (FecB) and Inverdale (FecXI) genes influence ovarian
development in early foetal life
P. Smith, W-S. O, D.A. Heath, N.L. Hudson, G.H. Davis, K.P.
McNatty
Wallaceville Animal Research Centre, P.O. Box 40063, Upper Hutt,
New Zealand
Proceedings of the New Zealand Society of Animal Production. 1993,
53: 281-286
The aim of this study was to gain evidence that the FecB and FecXI
genes influence ovarian development in foetal life. Foetuses which were
homozygous carriers of the Booroola gene (BB), Inverdale gene (II),
heterozygous carriers of the Inverdale gene (I+) and non-carriers of both the
Booroola (++) and Inverdale genes (++) were recovered at days 40 or 90 of
gestation. To eliminate the effects of litter size in the Booroola study, equal
numbers of BB and ++ embryos were transferred to recipient ewes.
Subsequently no gene-specific differences in litter size were noted at the
equivalent of days 40 and 90 of gestation. From these studies the FecB gene
was shown to affect body weight, the weight of the mesonephros, and
development of germ cells. In essence, at day 40 the mean body weight and
mean weight of the mesonephros were lighter in the BB foetuses compared to
the ++ animals (P<0.05). Moreover the development of the BB ovaries
appeared to be retarded relative to that of the ++ ovaries with respect to
mitosis and meiosis of germ cells and also the timing of germ cell atresia. In
the Inverdale foetuses, which were recovered after natural matings,
differences were observed at the level of the ovary but none were noted with
respect to body weight, or weight of mesonephros. At day 40 of gestation the
ovaries of the putative II foetuses were significantly lighter (P<0.05) than
those of the I+ or control animals. Moreover at day 90 the ++ and putative II
ovaries contained significantly fewer (P<0.05) germ cells (i.e. ~110,000)
compared to those in the authentic or putative I+ animals (i.e. ~240,000).
The differences in either the Booroola or Inverdale foetuses were not
accompanied by any significant differences in plasma or pituitary
concentrations of follicle-stimulating hormone or plasma inhibin. The results
are consistent with the notion that the FecB and FecX genes influence ovarian
development in foetal life.
Keywords: NZSAPAB;
Mesonephros; pituitary; ovary; FSH; inhibin; germ cells; oogonia;
oocytes; follicles.
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Last Updated 25-01-1997
