While researchers have learned a lot about reproductive clocks in some animals, this study is unique in helping uncover at least part of the genetic basis for determining how the reproductive system shuts off in the fall and restarts in time for spring.
"This study offers some of the first insights into how changes in gene expression are associated with a seasonal clock," said Brian Prendergast, co-author of the study and a post-doctoral fellow in psychology at Ohio State University.
The study was published in the Dec. 10 issue of the Proceedings of the National Academy of Science.
The researchers found that the three genes transthyretin, T4-binding globulin, and albumin were turned on or off as part of an internal clock in hamsters. These genes help regulate levels of thyroid hormones in the hypothalamus, which is involved in controlling the hamsters' reproductive cycle.
Hamster reproductive cycles are tied to day length and the amount of daylight they are exposed to during part of the year, Prendergast said. But there's an interesting catch.