Genetics

While hybridization between distinct taxa can have undesirable implications, it can also result in increased genetic variability and potentially, the exchange of adaptive genes or traits. Adaptive variation acquired through introgressive hybridization may be particularly advantageous for species facing rapid environmental change. I investigated a novel, climate change-induced hybrid zone between two flying squirrel species: the southern (Glaucomys volans) and northern (G. sabrinus) flying squirrel. I was interested in the occurrence of hybridization and introgression, the type of selective pressures maintaining the hybrid zone and the potential for adaptive introgression. I found relatively low hybridization and introgression frequencies (1.7% and 2.9% of the population, respectively) and no evidence of selection on hybrids or backcrosses in particular environments. I conclude that the data are more consistent with a hybrid zone maintained by endogenous (environment-independent) selection. I tested for adaptive introgression using two functional genes: IGF-1 and CLOCK. I documented intermediate functional allele frequencies in backcrosses compared to parental populations, suggesting the alleles do not confer fitness advantages in backcrosses. Despite lack of evidence for current adaptive introgression, genetic admixture between G. volans and G. sabrinus may provide adaptive potential should these species face more rapid or drastic environmental change in the future.

Author Keywords: adaptive introgression, flying squirrel, Glaucomys sabrinus, Glaucomys volans, hybridization, introgression

Trinucleotide repeats (TNRs) are a class of highly polymorphic microsatellites which occur in neutral and non-neutral loci and may provide utility for individual- and population-identification. Exonic trinucleotide motifs, in particular, offer additional advantages for non-human species that typically utilize dinucleotide microsatellite loci. Specifically, the reduction of technical artifacts, greater separation of alleles and greater specificity of amplification products leading to more efficient multiplexing and cross-taxa utilization. This study aims to identify and characterize polymorphic trinucleotide repeats and conserved primer sequences which are conserved across Cervidae (deer) species and their potential for individual identification in forensic wildlife investigations. Chapter one provides a broad introduction to trinucleotide microsatellites, chapter two deals with data-mining TNRs and chapter three applies the identified TNRs as genetic markers for individual identification. Results demonstrate proof-of-concept that exonic TNRs are capable of giving random match probabilities low enough to be employed in individual identification of evidentiary samples.

Author Keywords: DNA typing, Exons, Genetic Markers, Individual Identification, Trinucleotide, Wildlife Forensics