Publications by authors named "Jessica A Rick"

2 Publications

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Investigating the morphological and genetic divergence of arctic char ( populations in lakes of arctic Alaska.

Ecol Evol 2021 Apr 5;11(7):3040-3057. Epub 2021 Mar 5.

Department of Watershed Sciences and the Ecology Center Utah State University Logan UT USA.

Polymorphism facilitates coexistence of divergent morphs (e.g., phenotypes) of the same species by minimizing intraspecific competition, especially when resources are limiting. Arctic char ( sp.) are a Holarctic fish often forming morphologically, and sometimes genetically, divergent morphs. In this study, we assessed the morphological and genetic diversity and divergence of 263 individuals from seven populations of arctic char with varying length-frequency distributions across two distinct groups of lakes in northern Alaska. Despite close geographic proximity, each lake group occurs on landscapes with different glacial ages and surface water connectivity, and thus was likely colonized by fishes at different times. Across lakes, a continuum of physical (e.g., lake area, maximum depth) and biological characteristics (e.g., primary productivity, fish density) exists, likely contributing to characteristics of present-day char populations. Although some lakes exhibit bimodal size distributions, using model-based clustering of morphometric traits corrected for allometry, we did not detect morphological differences within and across char populations. Genomic analyses using 15,934 SNPs obtained from genotyping by sequencing demonstrated differences among lake groups related to historical biogeography, but within lake groups and within individual lakes, genetic differentiation was not related to total body length. We used PERMANOVA to identify environmental and biological factors related to observed char size structure. Significant predictors included water transparency (i.e., a primary productivity proxy), char density (fish·ha), and lake group. Larger char occurred in lakes with greater primary production and lower char densities, suggesting less intraspecific competition and resource limitation. Thus, char populations in more productive and connected lakes may prove more stable to environmental changes, relative to food-limited and closed lakes, if lake productivity increases concomitantly. Our findings provide some of the first descriptions of genomic characteristics of char populations in arctic Alaska, and offer important consideration for the persistence of these populations for subsistence and conservation.
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http://dx.doi.org/10.1002/ece3.7211DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019052PMC
April 2021

Structural genomic variation leads to genetic differentiation in Lake Tanganyika's sardines.

Mol Ecol 2020 09 9;29(17):3277-3298. Epub 2020 Aug 9.

Department of Botany and Program in Ecology, University of Wyoming, Laramie, WY, USA.

Identifying patterns in genetic structure and the genetic basis of ecological adaptation is a core goal of evolutionary biology and can inform the management and conservation of species that are vulnerable to population declines exacerbated by climate change. We used reduced-representation genomic sequencing methods to gain a better understanding of genetic structure among and within populations of Lake Tanganyika's two sardine species, Limnothrissa miodon and Stolothrissa tanganicae. Samples of these ecologically and economically important species were collected across the length of Lake Tanganyika, as well as from nearby Lake Kivu, where L. miodon was introduced in 1959. Our results reveal differentiation within both S. tanganicae and L. miodon that is not explained by geography. Instead, this genetic differentiation is due to the presence of large sex-specific regions in the genomes of both species, but involving different polymorphic sites in each species. Our results therefore indicate rapidly evolving XY sex determination in the two species. Additionally, we found evidence of a large chromosomal rearrangement in L. miodon, creating two homokaryotypes and one heterokaryotype. We found all karyotypes throughout Lake Tanganyika, but the frequencies vary along a north-south gradient and differ substantially in the introduced Lake Kivu population. We do not find evidence for significant isolation by distance, even over the hundreds of kilometres covered by our sampling, but we do find shallow population structure.
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http://dx.doi.org/10.1111/mec.15559DOI Listing
September 2020