Toadal Isolation: Genetic Connectivity of the Western Toad (Anaxyrus boreas) along I-90 in the Snoqualmie Pass Area of Washington State

<p>Single-nucleotide polymorphisms (SNPs) were used to assess the genetic connectivity of western toad (<em>Anaxyrus boreas</em>) breeding populations along Interstate-90 near Snoqualmie Pass, WA. Sites north and south of the freeway were sampled during the breeding season of 2019. SNP loci were subsequently generated using the proprietary DArTseq^TM (Canberra, ACT, Australia) method. A total of 15,468 SNPs were used to calculate pairwise F_ST values and three distinct breeding populations were identified, two north and one south of I-90. All pairwise F_ST values between these sites were low (0.02) but significantly different from 0. The lowest pairwise F_ST was between the two sites that were furthest apart (11.6 km), indicating higher levels of connectivity along than across the freeway. A <em>de novo </em>discriminant analysis of principal components (DAPC) confirmed this division between sites on either side of I-90. Although I-90 is the most prominent potential barrier on the landscape, the Yakima River may also be contributing to this division. An <em>a priori </em>DAPC was able to distinguish between all populations with enough confidence to assign toads that were randomly encountered in the summer of 2019 to their most likely population of origin and will be a useful tool in future studies.</p>

Name thesis:degree_name

Master of Science (MS)

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2020

Author dc:creator

• Myers, Anneliese

Contributors dc:contributor

• Jason Irwin
• Alison Scoville
• Linda Raubeson

• Amphibian
• Connectivity
• SNP
• Wildlife Crossing Structure
• I-90 Corridor
• Snoqualmie Pass
• Population Biology

Repository record dc:identifier

https://digitalcommons.cwu.edu/etd/1371

OAI identifier oai:identifier

oai:digitalcommons.cwu.edu:etd-2396