Category: Chimeric Mouse

Live-Borns from XX but Not XY Oocytes: DISCUSSION(4)

The defect in the XY oocyte remains to be clarified. Hunt and LeMaire have reported a high frequency of precocious dissociation between the X and Y chromosomes in oocytes isolated from the B6.Ypos female mouse at the diakinesis/metaphase I stage. Accordingly, it is conceivable that the B6YTIR female may lose its embryos because of aneuploidy. […]

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Live-Borns from XX but Not XY Oocytes: DISCUSSION(3)

Absence of Live-Borns from XY Oocytes Despite the fertility of all chimeric females, no live-boms were produced from XY oocytes. This observation suggests that the presence of XX cells failed to make the XY oocyte competent for reproduction. Therefore, the developmental failure of the XY oocyte is most likely intrinsic to the oocyte itself, and […]

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Live-Borns from XX but Not XY Oocytes: DISCUSSION(1)

Predominant Development of Female Chimeras In the present study, all but one (89%) of the live-born chimeras, which were composed of B6.YTIR and XX BALB/c cells in varying proportions, developed the female phenotype. The only exception was a male with bilateral testes. This strong bias towards the female sex was unexpected. When chimeric mice are […]

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Live-Borns from XX but Not XY Oocytes: DISCUSSION(2)

Live-Borns from XX Oocytes After mating with normal males, all XX XY chimeric females produced progeny exclusively derived from XX oocytes irrespective of the degree of XY contribution in body formation. Therefore, the fertility of XX oocytes was not abolished by the presence of XY somatic cells. We have previously reported several abnormal aspects of the […]

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Live-Borns from XX but Not XY Oocytes: RESULTS(5)

Y-Labeling was also found in oocytes of XX BALB/c о XY B6.Y™ chimeric ovaries. In the ovary (#15) with the highest contribution of XY cells, all three preantral follicles identified contained oocytes with hybridization signals. In the ovaries (#14 and #2) with a high contribution of XY cells, hybridization signals were seen in the majority […]

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Live-Borns from XX but Not XY Oocytes: RESULTS(4)

The ovaries from three XX BALB/c XX B6* chimeric females (#3, #13, #20) at 87, 157, and 88 dpp, respectively, were compared (Table 4, Fig. 4, d and e). They contained comparable numbers of follicles at various stages irrespective of age, although the number was slightly lower than in the majority of XX BALB/c XY […]

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Live-Borns from XX but Not XY Oocytes: RESULTS(3)

In XX <н> XX chimeric females, the contribution of B6* and BALB/c cells was deduced only from coat-color chi-merism (Table 3). All seven females had a dominant area or equal area of black coat color. Two females (#20 and #25) became pregnant after the first mating, and the rest did so at the second trial. […]

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