Environmental DNA Metagenomics
Environmental DNA (eDNA) is DNA that is released into the environment by living organisms from sources such as cells shed from skin, blood, saliva, and excrement, gametes, and from decomposing organisms. The presence and abundance of eDNA molecules in the environment provides biologists with a powerful tool for detecting and monitoring organisms. Methods for eDNA sampling have been in development and use for over a decade, and the science of eDNA sampling to detect and monitor the presence and distribution of species, particularly in aquatic environments, has advanced substantially. The Missouri Department of Conservation (MDC) monitoring and management program relies on species detection and biodiversity assessment. The primary goals of our project are to assess sensitivity and repeatability of eDNA metagenomic survey methods, and to enhance the reference database for mitogenomic sequences of Missouri fishes, so that these methods may be incorporated into MDC monitoring programs.
Current projects:
- Assessment of eDNA methods of biodiversity sampling
- Mitogenome sequencing for enhancement of public reference databases
- eDNA sampling of other taxonomic groups, including crayfish
Topminnow Evolutionary Ecology
Current research focuses on ecological speciation, hybridization, gene introgression, pre- and post-zygotic reproductive isolation, and the evolutionary role of chromosomal rearrangements in fish genomes. Much of our work is focused on a group of topminnows in the genus Fundulus. Members of this group include the blackspotted topminnow (F. olivacues), the blackstripe topminnow (F. notatus) and the broadstripe topminnow (F. euryzonus). This group of species exhibits a broad range throughout drainages in central and southern North America, including much of the Mississippi River and it’s tributaries as well as Gulf coastal drainages from Florida to Texas. The geographic ranges of these topminnows are broadly overlapping, with co-occurrence of species in numerous drainage systems. Within co-occurrence drainages, topminnows typically exhibit headwater or large river habitat specialization, and contact zones commonly occur at tributary-river confluences. The dynamics of hybridization and introgression vary considerably among drainages . We are focused on the causes and consequences of variations in mechanisms of reproductive isolation, and intrinsic and extrinsic barriers to genetic exchange.
Current projects:
- Hybrid zone dynamics and reproductive isoation in topminnows
- Mapping of chromosomal rearrangements using SNP markers
- Phylogeography of topminnow in the F. notatus complex
- Mating behavior in stream mesocoms
Phylogeography of Bigmouth Shiner
The Bigmouth Shiner, Notropis dorsalis, exhibits a broad geographic distribution that encompasses most of the upper Missouri and Mississippi River drainages as well as tributary streams of the Great Lakes. It’s distribution extends from Wyoming and Colorado to western New York and Pennsylvania. We are using mitochondrial and nuclear gene markers to reconstruct drainage relationships. We are finding that disjunct populations in the eastern part of their distribution are substantially divergent from populations throughout the central and western portion of their range.
