Evolutionary Significant Units (ESUs) are used by conservation managers to provide a rationale for prioritizing taxa for conservation efforts given limited resources. A practical extension of this approach is to identify evolutionary significant areas in which many species demonstrate phylogeographic structure. The upper portion of the Mississippi River Basin may represent an evolutionary significant area given low species-diversity and environmental-resistance values, and its unique geological history.
Genetic markers may assist current management efforts by assessing conservation units, resolving taxonomically difficult groups, detecting rare or cryptic species, and exploring evolutionary trajectories. The goal of this project is to demonstrate how genetic techniques can be integrated with other techniques to offer new management insights within the Missouri River Basin.
One of the potential threats to the Missouri River Basin is the introduction of invasive species. There is considerable debate about which life-history characteristics facilitate invasion. We will explore how invasion successes of fishes in Nebraska relate to biological characteristics, including fecundity, size and propagule pressure.
Hybridization may foster invasiveness by increasing genetic diversity and ultimately enhancing adaptation in novel environments. This phenomenon may explain the successful invasion of two sympatric Asian carps, bighead carp and silver carp, in the Missouri River basin. Genetic markers have been developed that now allow us to explore the extent of hybridization of these two species. If hybridization facilitated this invasion, then we expect a greater rate of hybridization in the Missouri River Basin compared to native ranges in China.
The stability of mitochondrial genomes in addition to their high mutation rate and relatively low number of genes make mitochondrial genomes ideal markers to begin addressing some of the evolutionary questions and conservation concerns of native species. However, a major limitation for genetic studies in the Missouri River Basin is the lack of a genetic database. We will begin to develop a genetic database with a primary focus towards native fish genomes because there are relatively few native fishes in Nebraska (i.e., doable) and fishes represent the largest invasive taxa in Nebraska. We will also include the mitochondrial genome of the Northern Long Eared Bat (Myotis septentrionalis) to showcase the functionality of mitochondrial genomes across diverse taxa.
GoalsProject objectives are to 1) determine which biological characteristics facilitate fish invasions within this region, 2) determine if hybridization occurs within other populations of bighead and silver carp or if it’s driven by novel environments, and 3) establish a mitochondrial genomic repository for this region.
Thus far, we have determined that species origin, degree of parental care, fecundity, lifespan, and propagule pressure were critical biological characteristics of invasive fishes that facilitated establishment within the USA. We have determined that hybridization rates between bighead carp and silver carp are similar in environments within native (12% in China) and non-native (13% in USA) ranges, counter to our a priori expectation that hybridization rates would be substantially greater in novel environments of the non-native range. To this point, we have collected and extracted mitochondrial DNA from 62 native species, including 61 native fishes and Myotis septentrionalis. These mitochondrial genomes are currently being sequenced.
Principal Investigator(s)-Kevin L. Pope, NE CFWRU
-Guoqing Gu, University of Nebraska at Omaha
-Sarah J. Gaughan
Graduate Student(s)-Sarah Gaughan, Ph.D.
Project DurationJune 2016-present
Funding-National Science Foundation EAPSI program
-National Science Foundation EO3 program