The global decline of freshwater mussels emphasizes the need to establish genetic resources to better understand their biology, including a unique mitochondrial biology known as doubly uniparental ...inheritance. In this study, we present the complete male-type (M-type) mitochondrial genome of the freshwater mussel, Potamilus streckersoni Smith, Johnson, Inoue, Doyle, & Randklev, 2019. The M-type mtDNA is approximately 16 kilobases and contains 22 tRNAs, two rRNAs, and 14 protein-coding genes, including a male-specific open reading frame. Read coverage revealed that M-type mtDNA was more abundant than female-type mtDNA in male gonadal tissue, with respect to a non-spawning male individual. Novel mitogenomes were resolved within previously described sex-specific monophyletic clades across the subfamily Ambleminae. The availability of high-quality nuclear and mitochondrial genomic data for P. streckersoni makes it a model for future research into the potential role of mtDNA in sex determination or sexual development in freshwater mussels.
Animal and plant species exhibit an astonishing diversity of sexual systems, including environmental and genetic determinants of sex, with the latter including genetic material in the mitochondrial ...genome. In several hermaphroditic plants for example, sex is determined by an interaction between mitochondrial cytoplasmic male sterility (CMS) genes and nuclear restorer genes. Specifically, CMS involves aberrant mitochondrial genes that prevent pollen development and specific nuclear genes that restore it, leading to a mixture of female (male‐sterile) and hermaphroditic individuals in the population (gynodioecy). Such a mitochondrial‐nuclear sex determination system is thought to be rare outside plants. Here, we present one possible case of CMS in animals. We hypothesize that the only exception to the strict maternal mtDNA inheritance in animals, the doubly uniparental inheritance (DUI) system in bivalves, might have originated as a mitochondrial‐nuclear sex‐determination system. We document and explore similarities that exist between DUI and CMS, and we propose various ways to test our hypothesis.
Cytoplasmic male sterility (CMS) refers to disruption of viable pollen production in plants as the result of mitonuclear interactions. CMS is rare outside plants. We hypothesize that the system of doubly uniparental inheritance (DUI) of mitochondria in bivalves originated as a CMS system and propose different ways to test our hypothesis.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Inaccurate systematics confound our ability to determine evolutionary processes that have led to the diversification of many taxa. The North American freshwater mussel tribe Lampsilini is one of the ...better-studied groups in Unionidae, however, many supraspecific relationships between lampsiline genera remain unresolved. Two genera previously hypothesized to be non-monophyletic that have been largely overlooked are Leptodea and Potamilus. We set out to resolve supraspecific relationships in Lampsilini and test the monophyly of Leptodea and Potamilus by integrating molecular, morphological, and life history data. Our molecular matrix consisted of four loci: cytochrome c oxidase subunit 1 (CO1), NADH dehydrogenase subunit 1 (ND1), internal transcribed spacer 1 (ITS1), and 28S ribosomal RNA. Secondly, we performed both traditional and Fourier shape morphometric analyses to evaluate morphological differences and finally, we compared our results with available life history data. Molecular data supported the paraphyly of both Leptodea and Potamilus, but nodal support was insufficient to make any conclusions regarding generic-level assignments at this time. In contrast, inference from our integrative taxonomic assessment depicts significant support for the recognition of a new species, Potamilus streckersoni sp. nov., the Brazos Heelsplitter. Our data show clear separation of three taxonomic entities in the P. ohiensis species complex: P. amphichaenus, P. ohiensis, and P. streckersoni sp. nov.; all molecularly, geographically, and morphologically diagnosable. Our findings have profound implications for unionid taxonomy and will aid stakeholders in establishing effective conservation and management strategies.
http://www.zoobank.org/urn:lsid:zoobank.org:pub:502647C0-418B-4CC4-85A8-BD89FC3F674F
Full text
Available for:
BFBNIB, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
North American freshwaters are among the world’s most threatened ecosystems, and freshwater mussels are among the most imperiled inhabiting these systems. A critical aspect of conservation biology is ...delineating patterns of genetic diversity, which can be difficult when a taxon has been extirpated from a significant portion of its historical range. In such cases, evaluating conservation and recovery options may benefit by using surrogate species as proxies when assessing overall patterns of genetic diversity. Here, we integrate the premise of surrogate species into a comparative phylogeographic framework to hypothesize genetic relationships between extant and extirpated populations of Potamilus inflatus by characterizing genetic structure in co-distributed congeners with similar life histories and dispersal capabilities. Our mitochondrial and nuclear sequence data exhibited variable patterns of genetic divergence between Potamilus spp. native to the Mobile and Pascagoula + Pearl + Pontchartrain (PPP) provinces. However, hierarchical Approximate Bayesian Computation indicated that the diversification between Mobile and PPP clades was synchronous and represents a genetic signature of a common history of vicariance. Recent fluctuations in sea-level appear to have caused Potamilus spp. in the PPP to form a single genetic cluster, providing justification for using individuals from the Amite River as a source of brood stock to re-establish extirpated populations of P. inflatus. Future studies utilizing eDNA and genome-wide molecular data are essential to better understand the distribution of P. inflatus and establish robust recovery plans. Given the imperilment status of freshwater mussels globally, our study represents a useful methodology for predicting relationships among extant and extirpated populations of imperiled species.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Aim
Biogeography seeks to identify and explain the spatial distributions of species and has become an important tool used by conservationists to protect and manage aquatic organisms. Texas, located ...in the southwestern United States, is home to 52 species of freshwater mussels, 9 of which are endemic to Texas and 7 that are endemic to Texas and neighboring states or countries. There have been two major attempts to classify this fauna into biogeographical provinces; however, both efforts relied on limited distribution information and outdated taxonomy. To address both issues, we set out to delineate biogeographic provinces for freshwater mussels in Texas by using a comprehensive distributional dataset of >28,000 records and molecular information.
Location
Southwestern United States.
Methods
We compiled community and molecular data for 48 of the 52 freshwater mussel species that occur in Texas. We performed algorithmic hierarchal cluster analysis (HCA) and nonmetric multidimensional scaling (NMDS) based on Euclidean distance to identify biogeographic groupings. We conducted a similar analysis using molecular sequence data for our target species.
Results
Based on the results from community and molecular data, we identified seven biogeographic provinces for freshwater mussels in Texas: Great Plains, Mississippi Embayment, Sabine‐Neches, Trinity‐San Jacinto, Central Texas, Rio Grande and Coastal. However, the Coastal and Great Plains provinces were not included in our analysis and were recognized based on previous work.
Main conclusions
Our approach integrating community and molecular datasets provides a comprehensive assessment of the biogeography of freshwater mussels in Texas, which serves as a model for future biogeographic studies. Our findings also shed light on the ecological, evolutionary and geologic processes shaping freshwater mussel communities in Texas, which is important for the conservation of remaining biodiversity in the state.
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Vitamin A is vital to maternal-fetal health and pregnancy outcomes. However, little is known about pregnancy associated changes in maternal vitamin A homeostasis and concentrations of circulating ...retinol metabolites. The goal of this study was to characterize retinoid concentrations in healthy women (
= 23) during two stages of pregnancy (25-28 weeks gestation and 28-32 weeks gestation) as compared to ≥3 months postpartum. It was hypothesized that plasma retinol, retinol binding protein 4 (RBP4), transthyretin and albumin concentrations would decline during pregnancy and return to baseline by 3 months postpartum. At 25-28 weeks gestation, plasma retinol (-27%), 4-oxo-13-
-retinoic acid (-34%), and albumin (-22%) concentrations were significantly lower, and
-retinoic acid (+48%) concentrations were significantly higher compared to ≥3 months postpartum in healthy women. In addition, at 28-32 weeks gestation, plasma retinol (-41%), retinol binding protein 4 (RBP4; -17%), transthyretin (TTR; -21%), albumin (-26%), 13-
-retinoic acid (-23%) and 4-oxo-13-
-retinoic acid (-48%) concentrations were significantly lower, whereas plasma
-retinoic acid concentrations (+30%) were significantly higher than ≥3 months postpartum. Collectively, the data demonstrates that in healthy pregnancies, retinol plasma concentrations are lower, but
-retinoic acid concentrations are higher than postpartum.
Abstract
In most animals, mitochondrial DNA is strictly maternally inherited and non-recombining. One exception to this pattern is called doubly uniparental inheritance (DUI), a phenomenon involving ...the independent transmission of female and male mitochondrial genomes. DUI is known only from the molluskan class Bivalvia. The phylogenetic distribution of male-transmitted mitochondrial DNA (M mtDNA) in bivalves is consistent with several evolutionary scenarios, including multiple independent gains, losses, and varying degrees of recombination with female-transmitted mitochondrial DNA (F mtDNA). In this study, we use phylogenetic methods to test M mtDNA origination hypotheses and infer the prevalence of mitochondrial recombination in bivalves with DUI. Phylogenetic modeling using site concordance factors supported a single origin of M mtDNA in bivalves coupled with recombination acting over long evolutionary timescales. Ongoing mitochondrial recombination is present in Mytilida and Venerida, which results in a pattern of concerted evolution of F mtDNA and M mtDNA. Mitochondrial recombination could be favored to offset the deleterious effects of asexual inheritance and maintain mitonuclear compatibility across tissues. Cardiida and Unionida have gone without recent recombination, possibly due to an extension of the COX2 gene in male mitochondrial DNA. The loss of recombination could be connected to the role of M mtDNA in sex determination or sexual development. Our results support that recombination events may occur throughout the mitochondrial genomes of DUI species. Future investigations may reveal more complex patterns of inheritance of recombinants, which could explain the retention of signal for a single origination of M mtDNA in protein-coding genes.
Limited data are available on the effects of pregnancy on the maternal metabolome. Therefore, the objective of this study was to use metabolomics analysis to determine pathways impacted by pregnancy ...followed by targeted confirmatory analysis to provide more powerful conclusions about metabolic alterations during pregnancy. Forty-seven pregnant women, 18-50 years of age were included in this study, with each subject serving as their own control. Plasma samples were collected between 25 and 28 weeks gestation and again ≥3 months postpartum for metabolomics analysis utilizing an HILIC/UHPLC/MS/MS assay with confirmatory targeted specific concentration analysis for 10 of the significantly altered amino acids utilizing an LC/MS assay. Principle component analysis (PCA) on metabolomics data clearly separated pregnant and postpartum groups and identified outliers in a preliminary assessment. Of the 980 metabolites recorded, 706 were determined to be significantly different between pregnancy and postpartum. Pathway analysis revealed three significantly impacted pathways, arginine biosynthesis (
= 2 × 10
and FDR = 1 × 10
), valine, leucine, and isoleucine metabolism (
= 2 × 10
and FDR = 2 × 10
), and xanthine metabolism (
= 4 × 10
and FDR = 4 × 10
). Of these we focused analysis on arginine biosynthesis and branched-chain amino acid (BCAA) metabolism due to their clinical importance and interconnected roles in amino acid metabolism. In the confirmational analysis, 7 of 10 metabolites were confirmed as significant and all 10 confirmed the direction of change of concentrations observed in the metabolomics analysis. The data support an alteration in urea nitrogen disposition and amino acid metabolism during pregnancy. These changes could also impact endogenous nitric oxide production and contribute to diseases of pregnancy. This study provides evidence for changes in both the ammonia-urea nitrogen and the BCAA metabolism taking place during pregnancy.
Abstract
Past geological processes and climate change affected current species distributions and the genetic structure of riverine fauna. Western Gulf of Mexico coastal rivers harbour four mussel ...species within the genus Fusconaia (Bivalvia: Unionida). The distributions of these species are unclear owing to their indistinguishable shell morphologies. Using molecular phylogenetic and Fourier morphometric analyses, we examined phylogenetic relationships and morphological variation among the species and made inferences about the role of past geological and climatic factors in shaping the current genetic structure and distributions of these species in the region. Our results showed the presence of three Fusconaia species within the region: Fusconaia askewi, Fusconaia chunii and Fusconaia flava. We confirmed that Fusconaia lananensis is a junior synonym of F. askewi and that F. chunii is genetically distinct from F. askewi. The Trinity River has syntopic F. flava whose morphologies are indistinguishable from those of F. chunii. Divergence-time estimates matched major geological and climatic events in the region, where climate-driven river formations during the mid-Miocene to Pleistocene caused major diversification of Fusconaia species. Knowledge gained from the present study provides a better understanding of vicariant events that shaped current species distributions and helps to identify conservation priorities that apply to the Fusconaia species.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
ABSTRACT
Truncilla macrodon¸ the Texas Fawnsfoot, is currently considered to be restricted to the Brazos and Colorado river drainages in central Texas, USA. Subfossil specimens resembling T. macrodon ...from shell middens in the Trinity river drainage have raised questions about its presumptive range. Extant Truncilla populations occupying the Trinity river drainage are believed to be Truncilla donaciformis, the Fawnsfoot, but the species identity has not been assessed using molecular techniques. In this study, we set out to use phylogeographic and morphometric approaches to resolve the distribution of Truncilla spp. in Texas, with an emphasis on assessing species identity of Truncilla in the Trinity river drainage. Our molecular analyses indicated individuals from the Trinity river drainage are T. macrodon rather than T. donaciformis, and morphometric analyses using ratios of shell length, width and height supports this finding and showed differentiation among T. macrodon, Truncilla cognata and T. donaciformis. These combined findings suggest the range of T. macrodon is larger than previously recognized and includes the Colorado, Brazos and Trinity river drainages. The status of Truncilla spp. in the San Jacinto river basin remains unclear due to lack of information on historical or extant populations, but we recommend conservationists consider T. macrodon as part of the mussel fauna since the drainage shares an embayment with the Trinity river drainage. Molecular data also indicated the Trinity population of T. macrodon is distinct from, and more genetically diverse than, the Brazos and Colorado populations. This difference suggests the Trinity River population should be treated as a separate management unit from the Brazos and Colorado River populations to facilitate effective conservation and recovery planning. Our study adds to the growing body of literature highlighting the utility of molecular data in conservation and management of freshwater mussels.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
PDF
