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Faculty Sponsor

Dr. Mark Jordan


Department of Biology

University Affiliation

Indiana University – Purdue University Fort Wayne


The transformation of headwater streams to assist in draining excess water from agricultural fields is associated with increased variation in stream flow, simplified in-stream habitats and reduced water quality. The creek chub (Semotilus atromaculatus) is an abundant species of fish found inhabiting these altered environments, that appears to be tolerant to disturbance. To better understand possible evolutionary responses to ecological disturbance in channelized streams, we analyzed a large number of genetic markers in populations occupying streams with contrasting levels of disturbance. We used amplified fragment length polymorphism (AFLP) to screen genetic variation in 116 fish sampled from streams within the St. Joseph River watershed: one in northeastern Indiana with land cover dominated by agriculture land cover and two others in southern Michigan that includes one relatively undisturbed stream running through a forested game reserve. If there is a selection for tolerance in channelized ditches we hypothesize that a handful of ALFP loci will show greater differentiation than that found among the majority of the markers. Genetic variation from AFLP loci will also be compared to patterns of genetic variation observed in an earlier analysis that relied on a different type of genetic marker (microsatellites).


Biology | Life Sciences

Stream Channelization and the Genetic Diversity of Creek Chubs (Semotilus atromaculatus)

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