Genetic basis and consequences of variation in seasonal timing.
Golczer Gatti, Gabriel.
2019
-
In temperate environments, organisms need to adapt to the seasonal cycle by synchronizing the timing of their life cycle (phenology). Although this synchronization is paramount for their survival and reproduction, we do not understand the genetic basis and molecular mechanisms involved in this process. Moreover, we haven't explored the consequences of the variability in seasonal timing traits, such ... read moreas dormancy, for many evolutionary processes for example adaptation/survival, reproduction, and speciation. My dissertation investigates the genetic architecture and molecular mechanism behind seasonal timing, as well as consequences in variability of seasonal timing traits, adding to the newly expanding body of literature on seasonal biology. I first characterized dormancy initiation of 3 genetic lines of the European Corn Borer moth (ECB). After determining the environments at which they respond, I created pedigree lines to map the genetic basis of the diapause initiation trait. I found that the responsible genetic basis is located in the sex chromosome, specifically in the rearranged region. This finding, accompanied by the inheritance pattern found, reveals the complex genetic architecture of the traits that determine the seasonal timing of the ECB in temperate environments. Next, I investigate genes and regions of the genome showing signatures of natural selection. Due to the strong selective pressures that environments inflict on seasonal traits, I expect to observe such signatures in genes involved in the aforementioned traits. Leveraging genomic information of 8 populations of ECB, I scan for signatures of selection across the genome in order to create a list of candidate genes for the genetic basis of seasonal timing traits, and other traits associated with seasonal phenotypes. I found 9 genes of interest with evidence from previous studies that point to their involvement in the mechanism behind seasonal timing and other reproductive barriers. And in a final study, I test if seasonal timing differences are strong enough to impede gene flow between two ECB types with different voltinism. I estimated the amount of gene flow, migration and population structuring between different seasonal flights from genetic information. I found a consistent pattern of reproductive isolation that is weaker than other reproductive isolation barriers, e.g., mating pheromone difference. Therefore, concluding that the maintenance of the different generations in environments where two seasonal types where ECB occurs is held by natural selection or assortative mating without complete reproductive isolation.
Thesis (Ph.D.)--Tufts University, 2019.
Submitted to the Dept. of Biology.
Advisor: Erik Dopman.
Committee: Elizabeth Crone, Phillip Starks, and Sean Mullen.
Keywords: Biology, Evolution & development, and Genetics.read less - ID:
- b85161411
- To Cite:
- TARC Citation Guide EndNote
