Geology topics

Aaron Aunins

Publications and source records attributed to Aaron Aunins.

21 records · Page 2Linked to original sources

USGS2016

Comparative mitogenomic analyses of three North American stygobiont amphipods of the genus Stygobromus (Crustacea: Amphipoda)

The mitochondrial genomes of three North American stygobiont amphipods Stygobromus tenuis potomacus , S. foliatus and S. indentatus collected from Caroline County, VA, were sequenced using a shotgun sequencing approach on an Illumina NextSeq500 (Illumina Inc., San Diego, CA). All three mitogenomes displayed 13 protein-coding genes, 22 tRNAs and two rRNAs typical of metazoans. While S. tenuis and S. indentatus displayed identical gene orders similar to the pancrustacean ground pattern, S. foliatus displayed a transposition of the trnL2 - cox2 genes to after atp8-atp6 . In addition, a short atp8 gene, longer rrnL gene and large inverted repeat within the Control Region distinguished S. foliatus from S. tenuis potomacus and S. indentatus . Overall, it appears that gene order varies considerably among amphipods, and the addition of these Stygobromus mitogenomes to the existing sequenced amphipod mitogenomes will prove useful for characterizing evolutionary relationships among various amphipod taxa, as well as investigations of the evolutionary dynamics of the mitogenome in general.

Mitochondrial DNA Part B↗

USGS2014

A nuclear DNA perspective on delineating evolutionarily significant lineages in polyploids: the case of the endangered shortnose sturgeon ( Acipenser brevirostrum )

The shortnose sturgeon, Acipenser brevirostrum , oft considered a phylogenetic relic, is listed as an “endangered species threatened with extinction” in the US and “Vulnerable” on the IUCN Red List. Effective conservation of A. brevirostrum depends on understanding its diversity and evolutionary processes, yet challenges associated with the polyploid nature of its nuclear genome have heretofore limited population genetic analysis to maternally inherited haploid characters. We developed a suite of polysomic microsatellite DNA markers and characterized a sample of 561 shortnose sturgeon collected from major extant populations along the North American Atlantic coast. The 181 alleles observed at 11 loci were scored as binary loci and the data were subjected to multivariate ordination, Bayesian clustering, hierarchical partitioning of variance, and among-population distance metric tests. The methods uncovered moderately high levels of gene diversity suggesting population structuring across and within three metapopulations (Northeast, Mid-Atlantic, and Southeast) that encompass seven demographically discrete and evolutionarily distinct lineages. The predicted groups are consistent with previously described behavioral patterns, especially dispersal and migration, supporting the interpretation that A. brevirostrum exhibit adaptive differences based on watershed. Combined with results of prior genetic (mitochondrial DNA) and behavioral studies, the current work suggests that dispersal is an important factor in maintaining genetic diversity in A. brevirostrum and that the basic unit for conservation management is arguably the local population.

PLoS ONE↗

USGS2014

River mainstem thermal regimes influence population structuring within an Appalachian brook trout population

Brook trout ( Salvelinus fontinalis ) often exist as highly differentiated populations, even at small spatial scales, due either to natural or anthropogenic sources of isolation and low rates of dispersal. In this study, we used molecular approaches to describe the unique population structure of brook trout inhabiting the Shavers Fork watershed, located in eastern West Virginia, and contrast it to nearby populations in tributaries of the upper Greenbrier River and North Fork South Branch Potomac Rivers. Bayesian and maximum likelihood clustering methods identified minimal population structuring among 14 collections of brook trout from throughout the mainstem and tributaries of Shavers Fork, highlighting the role of the cold-water mainstem for connectivity and high rates of effective migration among tributaries. In contrast, the Potomac and Greenbrier River collections displayed distinct levels of population differentiation among tributaries, presumably resulting from tributary isolation by warm-water mainstems. Our results highlight the importance of protecting and restoring cold-water mainstem habitats as part of region-wide brook trout conservation efforts. In addition, our results from Shavers Fork provide a contrast to previous genetic studies that characterize Appalachian brook trout as fragmented isolates rather than well-mixed populations. Additional study is needed to determine whether the existence of brook trout as genetically similar populations among tributaries is truly unique and whether connectivity among brook trout populations can potentially be restored within other central Appalachian watersheds.

West Virginia↗