Date Approved


Date Posted


Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)



Committee Member

Katherine Greenwald, Ph.D., Chair

Committee Member

Margaret Hanes, Ph.D.

Committee Member

Steven Francoeur, Ph.D.


Unisexual Ambystoma produce ploidy-variable offspring that differ in survivorship to adulthood. These populations reproduce through kleptogenesis, persisting by stealing genetic material from males of compatible bisexual Ambystoma species (e.g., Jefferson's Salamander A. jeffersonianum, and the Blue-Spotted Salamander A. laterale). Kleptogenesis can result in ploidy-variable embryos within an egg mass because the female may or may not incorporate the male ambystomatid genome. Little is known about the survivorship of ploidy-variable individuals. In previous studies, triploid individuals are the most abundant class, suggesting a greater mortality in high-ploidy (tetraploid and pentaploid) individuals. We assessed the frequency of ploidy levels (determined by microsatellite analysis) across four life stages within a single year: adults, early larvae, late larvae, and metamorphs. We found that, instead of an abrupt change due to individuals dying at or during metamorphosis, there was a gradual decline in tetraploids across all stages as the larvae develop into adults.

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Biology Commons