Date Approved


Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department or School


Committee Member

Katherine Greenwald

Committee Member

Margaret Hanes

Committee Member

Allen Kurta


The geographic origin of Michigan’s Trachemys scripta elegans has been a contentious subject since its first description in 1934. At that time two explanations were proposed: 1) populations of T. s. elegans are native to Michigan and naturally expanded their range from Ohio and Indiana; or 2) populations are non-native and have been introduced by humans via the pet-trade from throughout the United States. To differentiate between these possibilities, I compare the genetic structure of six populations throughout Indiana, Michigan, and Ohio, using six microsatellite markers. No isolation-by-distance was detected and model-based statistics support two genetic clusters with five populations from Michigan, Ohio, and Indiana forming one cluster and a single Michigan population forming a second. These results indicate that some of Michigan's populations of T. s. elegans are composed of released pets from geographically distant sources, while others are either native relicts or have been introduced from nearby populations.

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