Good day ma’am! Thank you very much for your interest in our presentation and for your queries. To answer them, we shall be using supplementary research as well in order to provide more comprehensive answers.
1. There was mention in the introduction of oogenesis occurring in most animals. Can you mention exception to this where oogenesis does not occur in the ovaries? Perhaps a better way of phrasing this concept to avoid any confusion was that oogenesis occurs in the ovaries of all animals, while meiosis occurs before birth in most animals. This was also visually presented in one of our slides that stated, “Meiosis does not always begin before birth.” There are no exceptions wherein oogenesis would occur in places other than the ovaries.
2. Please summarize the factors that affect oogenesis in hamsters. Factors that affect oogenesis in hamsters include:
- Critical time for when oogonia can complete meiotic prophase or survive in in vitro culture → ideally between 14-15 days post coitum / after mating
- Genetics - oogonia may be 'programmed' to undergo meiosis at a time that is characteristic of the given species
- Endocrine control - Hormones in the form of steroids are yet to be determined if they affect the initiation of meiosis in females
3. Will female hamsters show peculiar features in their reproduction as a result of this unique feature of meiosis occurring after birth? No studies have shown that female hamsters exhibit peculiar features in their reproduction as a result of their delayed onset of meiosis. The only observable differences are that male hamsters are able to reach sexual maturity earlier than females, and that female hamsters which breed earlier than 10 weeks are more prone to giving birth to still-born pups — these, however, are not yet proven to be results of delayed meiosis. Other than that, hamsters are generally similar to their close relatives, rats, who exhibit meiosis before birth. They both have a short and consistent estrous cycle (4 days), a predictable time of ovulation, and a short gestation period (16 days) (Chanut & Williams, 2015).
References:
Chanut, F. J. A., & Williams, A. M. (2015). The Syrian golden hamster estrous cycle: Unique characteristics, visual guide to staging, and comparison with the rat.
Toxicologic Pathology, 44(1). https://doi.org/10.1177/0192623315607668.
