Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School


First Advisor

Nels H. Granholm


The immediate objectives of the studies to be presented were (1) to establish the presence and characterize the morphology of the Ay/Ay homozygotes before and after implantation, (2) describe the relationship between embryo and uterus, (3) characterize prenatal and neonatal losses occurring to the Ay/a mouse, and (4) test the randomness of mating selection of the Ay/a mouse. To meet the objectives, data collected from the complete serial section of embryos in utero at 90 and 132 hours post coitum (hpc) from matings of yellow females (Ay/a) by yellow males (Ay/a) will be compared to yellow female by black male (a/a) matings. In utero analysis offers the assessment of embryo-uterine relationships and portrays the morphology of Ay/Ay expression in the dynamic uterine environment rather than the static in vitro culture. In vitro development of the Ay/Ay ‑embryo may provide misleading information concerning in vivo expression of the Ay gene. The uterine environment of the Ay/a female has been suggested to be antagonistic toward the development of Ay/Ay and Ay/a embryos as a result of a hormonal deficiency. Hormonal abnormalities, though not analyzed directly, may be evaluated by careful attention to mating selections of the Ay/a and a/a male, as well as survival of young before and after birth and to weaning in litters from Ay/a and a/a females. This thesis is organized on the following plan. Within the literature review homozygous Ay expression will be discussed first followed by information on the Ay in the heterozygous condition. Particular attention will be paid to heterozygous Ay effects on reproduction. Following that, reports of investigations completed are presented containing a short literature summary, methods, results, and discussion. Finally conclusions will be drawn in terms of the contribution of the experiments to the understanding of Ay expression.

Library of Congress Subject Headings

Mammals -- Embryology




South Dakota State University

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