Meeting Abstract
The mammalian copulatory plug, which coagulates after male ejaculation in the vaginal tract of females, is a well-studied target of sexual selection. The copulatory plug has been hypothesized to transport sperm, prevent rival male insemination., and stimulate females. Transglutaminase 4 (TGM4) has been shown to be an essential protein for the solidification of male ejaculate, and unlike other copulatory plug proteins does not appear to affect sperm quality or speed. The TGM4 knockout mouse model (Mus domesticus) lacks a copulatory plug but does not show any obvious differences in body weight or frequency of copulation, yet they show a remarkable decrease in the number of litters sired. This system therefore allows us to directly test the significance of the copulatory plug, specifically its importance to reproductive success. In this study, I have attempted to isolate at which specific stages post-copulation female mice mated to TGM4ko/ko males have defective pregnancies. My results show that there is a decrease in (A) fertilization success, (B) the rate of implantation, yet no decrease in (C) offspring viability. Overall these results suggest that the copulatory plug plays a novel role in the early stages of offspring viability despite only being present for the first 24-48 hours.
