Date of Award

2011

Degree Name

Physical Science

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Ralph Oberly

Second Advisor

Michael Little

Third Advisor

Thomas Jones

Abstract

Blacknose dace (Rhinichthys) are one of the most common cyprinid fishes in eastern North America. They also have been a topic of debate for over 30 years because morphology-based systematics has failed to clearly define their taxa. Taxonomists classify the complex into two species and one subspecies: the eastern form, R. atratulus atratulus; and the western form R. obtusus obtusus, and southern form R. obtusus meleagris. This research uses the mitochondrial cytochrome b gene and genomic RAG 2 gene in a phylogenetic analysis to help clarify species relations according to differences between each current species. Maps have been created to give a visual representation of how these fish may have evolved from one another in their respective stream locations in West Virginia, both by morphological and genetic characteristics. Current results with the mitochondrial cytochrome b gene indicates that there is a distinct separation between R. atratulus atratulus and R. obtusus obtusus,R.atratlus atratulus having 51-58 site changes compared to the R. obtusus obtusus reference. The difference between R. obtusus obtusus and R. obtusus meleagris is not as direct. In the collection of R. obtusus obtusus two groupings were recorded. The first group had 0–5 differences; the second grouping had 10–19 base pair changes. The R. obtusus meleagris species group had 19–21 changes. The RAG2 genetic tree was composed of two branches, one mixed with R. obtusus obtusus and R.obtusus meleagris and a second composed of R. atratulus atratulus. Even though there are strong indications that these fish have been separated long enough to begin to look different through there mitochondrial lineage, there is evidence that the groups are interbreeding.

Subject(s)

Rhinichthys atratulus - West Virginia.

Rhinichthys atratulus - West Virginia - Morphology.

Rhinichthys atratulus - Ecology - West Virginia.

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