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Full-Text Articles in Life Sciences
Adaptation Reshapes The Distribution Of Fitness Effects, Diego Tenoch Morales Lopez
Adaptation Reshapes The Distribution Of Fitness Effects, Diego Tenoch Morales Lopez
Electronic Thesis and Dissertation Repository
The process of adaptation has been of interest since the XIX century, when Darwin first proposed the idea of natural selection. Since then, there has been a myriad of theoretical and empirical works that have expanded the field. From the many evolutionary insights these works have produced, a foundational idea is that spontaneous mutations in the genome of organisms can produce changes to their reproductive success that might confer an advantage for the mutant organisms with respect to their peers. Therefore, mutations drive adaptive evolution by virtue of their heritable effects on fitness. Empirical measures of the distribution of these …
Divergent Transcriptional Responses To Low Temperature Among Populations Of Alpine And Lowland Species Of New Zealand Stick Insects (Micrarchus)., Luke T Dunning, Alice B Dennis, Brent J Sinclair, Richard D Newcomb, Thomas R Buckley
Divergent Transcriptional Responses To Low Temperature Among Populations Of Alpine And Lowland Species Of New Zealand Stick Insects (Micrarchus)., Luke T Dunning, Alice B Dennis, Brent J Sinclair, Richard D Newcomb, Thomas R Buckley
Biology Publications
In widespread and genetically structured populations, temperature variation may lead to among-population differentiation of thermal biology. The New Zealand stick insect genus Micrarchus contains four species that inhabit different thermal environments, two of which are geographically widespread. RNA-Seq and quantitative PCR were used to investigate the transcriptional responses to cold shock among lowland and alpine species to identify cold-responsive transcripts that differ between the species and to determine whether there is intraspecific geographical variation in gene expression. We also used mitochondrial DNA, nuclear 28S ribosomal DNA and transcriptome-wide SNPs to determine phylogeographic structure and the potential for differences in genetic …
Introduced Chinook Salmon (Oncorhynchus Tshawytscha) In Lake Huron: Do They Spawn At The Right Time?, Meghan T. Gerson
Introduced Chinook Salmon (Oncorhynchus Tshawytscha) In Lake Huron: Do They Spawn At The Right Time?, Meghan T. Gerson
Electronic Thesis and Dissertation Repository
Chinook salmon (Oncorhynchus tshawytscha), following their introduction to the Great Lakes, have successfully colonized many tributaries. Under the hypothesis that colonization success is facilitated by intrinsic factors (i.e., preadaptation), I predicted that patterns of reproductive timing in an introduced population would show similarities with those in their native range. To test this prediction, attributes of reproductive timing were characterized in Chinook salmon from the Sydenham River, Ontario. In their native range, female Chinook salmon exhibit a seasonal decline in reproductive lifespan, a decline in fat stores, low egg retention at death (< 0.5%), and spawning at temperatures below 12.8°C. In contrast, Sydenham River Chinook salmon showed no seasonal decline in reproductive lifespan or fat stores and nineteen of twenty females had egg retention greater or equal to 0.5%. Also, many individuals (30%) spawned when water temperatures exceeded 12.8°C. Thus, individuals do not appear to be pre-adapted in this system.