scholarly journals Genome-wide SNPs redefines species boundaries and conservation units in the freshwater mussel genus Cyprogenia of North America

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kyung Seok Kim ◽  
Kevin J. Roe

AbstractDetailed information on species delineation and population genetic structure is a prerequisite for designing effective restoration and conservation strategies for imperiled organisms. Phylogenomic and population genomic analyses based on genome-wide double digest restriction-site associated DNA sequencing (ddRAD-Seq) data has identified three allopatric lineages in the North American freshwater mussel genus Cyprogenia. Cyprogenia stegaria is restricted to the Eastern Highlands and displays little genetic structuring within this region. However, two allopatric lineages of C. aberti in the Ozark and Ouachita highlands exhibit substantial levels (mean uncorrected FST = 0.368) of genetic differentiation and each warrants recognition as a distinct evolutionary lineage. Lineages of Cyprogenia in the Ouachita and Ozark highlands are further subdivided reflecting structuring at the level of river systems. Species tree inference and species delimitation in a Bayesian framework using single nucleotide polymorphisms (SNP) data supported results from phylogenetic analyses, and supports three species of Cyprogenia over the currently recognized two species. A comparison of SNPs generated from both destructively and non-destructively collected samples revealed no significant difference in the SNP error rate, quality and amount of ddRAD sequence reads, indicating that nondestructive or trace samples can be effectively utilized to generate SNP data for organisms for which destructive sampling is not permitted.

2021 ◽  
Author(s):  
Kevin Roe ◽  
Kyung Seok Kim

Abstract Detailed information on species delineation and population genetic structure is a prerequisite for designing effective restoration and conservation strategies for imperiled organisms. Phylogenomic and population genomic analyses based on genome-wide ddRAD-Seq data has identified three allopatric lineages in the North American freshwater mussel genus Cyprogenia. Cyprogenia stegaria is restricted to the Eastern Highlands and displays little genetic structuring within this region. However, two allopatric clusters of C. aberti in the Ozark and Ouachita highlands exhibit substantial levels (mean FST = 0.120) of genetic differentiation and each warrants recognition as a distinct evolutionary lineage. Lineages of Cyprogenia in the Ouachita and Ozark highlands are further subdivided reflecting structuring at the level of river systems. Species tree inference and species delimitation in a Bayesian framework using SNP data supported results from phylogenetic analyses, which favors recognizing three species of Cyprogenia over the currently recognized two species.A comparison of SNPs generated from both destructively and non-destructively collected samples revealed no significant difference in the SNP error rate, quality and amount of ddRAD sequence reads, indicating that nondestructive or trace samples can be effectively utilized to generate SNP data for organisms for which destructive sampling is not permitted.


2019 ◽  
Vol 15 ◽  
pp. 117693431988994
Author(s):  
Shulin Zhang ◽  
Yaling Cai ◽  
Jinggong Guo ◽  
Kun Li ◽  
Renhai Peng ◽  
...  

Determining the genetic rearrangement and domestication footprints in Gossypium hirsutum cultivars and primitive race genotypes are essential for effective gene conservation efforts and the development of advanced breeding molecular markers for marker-assisted breeding. In this study, 94 accessions representing the 7 primitive races of G hirsutum, along with 9 G hirsutum and 12 Gossypium barbadense cultivated accessions were evaluated. The genotyping-by-sequencing (GBS) approach was employed and 146 558 single nucleotide polymorphisms (SNP) were generated. Distinct SNP signatures were identified through the combination of selection scans and association analyses. Phylogenetic analyses were also conducted, and we concluded that the Latifolium, Richmondi, and Marie-Galante race accessions were more genetically related to the G hirsutum cultivars and tend to cluster together. Fifty-four outlier SNP loci were identified by selection-scan analysis, and 3 SNPs were located in genes related to the processes of plant responding to stress conditions and confirmed through further genome-wide signals of marker-phenotype association analysis, which indicate a clear selection signature for such trait. These results identified useful candidate gene locus for cotton breeding programs.


2019 ◽  
Author(s):  
M. Taylor Perkins ◽  
Tetyana Zhebentyayeva ◽  
Paul H. Sisco ◽  
J. Hill Craddock

AbstractThe genus Castanea in North America contains multiple tree and shrub taxa of conservation concern. The two species within the group, American chestnut (Castanea dentata) and chinquapin (C. pumila sensu lato), display remarkable morphological diversity across their distributions in the eastern United States and southern Ontario. Previous investigators have hypothesized that hybridization between C. dentata and C. pumila has played an important role in generating morphological variation in wild populations. A putative hybrid taxon, Castanea alabamensis, was identified in northern Alabama in the early 20th century; however, the question of its hybridity has been unresolved. We tested the hypothesized hybrid origin of C. alabamensis using genome-wide sequence-based genotyping of C. alabamensis, all currently recognized North American Castanea taxa, and two Asian Castanea species at >100,000 single-nucleotide polymorphism (SNP) loci. With these data, we generated a high-resolution phylogeny, tested for admixture among taxa, and analyzed population genetic structure of the study taxa. Bayesian clustering and principal components analysis provided no evidence of admixture between C. dentata and C. pumila in C. alabamensis genomes. Phylogenetic analysis of genome-wide SNP data indicated that C. alabamensis forms a distinct group within C. pumila sensu lato. Our results are consistent with the model of a nonhybrid origin for C. alabamensis. Our finding of C. alabamensis as a genetically and morphologically distinct group within the North American chinquapin complex provides further impetus for the study and conservation of the North American Castanea species.


DNA Research ◽  
2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Hiroto Kobayashi ◽  
Kenta Shirasawa ◽  
Nobuko Fukino ◽  
Hideki Hirakawa ◽  
Takashi Akanuma ◽  
...  

Abstract Radish (Raphanus sativus L.) is cultivated around the world as a vegetable crop and exhibits diverse morphological and physiological features. DNA polymorphisms are responsible for differences in traits among cultivars. In this study, we determined genome-wide single-nucleotide polymorphisms (SNPs) among geographically diverse radish accessions using the double-digest restriction site-associated DNA sequencing (ddRAD-Seq) method. A total of 52,559 SNPs was identified in a collection of over 500 radish accessions (cultivated and wild) from East Asia, South and Southeast Asia, and the Occident and Near East. In addition, 2,624 SNP sites without missing data (referred to as common SNP sites) were identified among 510 accessions. Genetic diversity analyses, based on the common SNP sites, divided the cultivated radish accessions into four main groups, each derived from four geographical areas (Japan, East Asia, South and Southeast Asia, and the Occident and Near East). Furthermore, we discuss the origin of cultivated radish and its migration from the West to East Asia. SNP data generated in this work will facilitate further genetic studies on the radish breeding and production of DNA markers.


Author(s):  
Katherine Beigel ◽  
Alix Matthews ◽  
Katrin Kellner ◽  
Christine Pawlik ◽  
Matthew Greenwold ◽  
...  

Over the past few decades, large-scale phylogenetic analyses of fungus-gardening ants and their symbiotic fungi have depicted strong concordance among major clades of ants and their symbiotic fungi, yet within clades, fungus sharing is somewhat widespread among unrelated ant lineages. These symbioses are thought to be explained by a diffuse coevolution model within major clades. Understanding horizontal exchange within clades has been limited by conventional genetic markers that lack both interspecific and geographic variation. To examine whether reports of horizontal exchange was indeed symbiont sharing or an issue of employing relatively uninformative molecular markers, samples of Trachymyrmex arizonensis and Trachymyrmex pomonae and their fungi were collected from native populations in Arizona and genotyped using conventional marker genes and genome-wide single nucleotide polymorphisms (SNPs). Conventional markers of the fungal symbionts generally exhibited cophylogenetic patterns that were consistent with some symbiont sharing, but most fungal clades had low support. SNP analysis, in contrast, indicated that each ant species exhibited fidelity to its own fungal subclade with only one instance of a colony growing a fungus that was otherwise associated with a different ant species. This evidence supports a pattern of codivergence between Trachymyrmex species and their fungi, and thus a diffuse coevolutionary model may not accurately predict symbiont exchange. These results suggest that fungal sharing across host species in these symbioses may be less extensive than previously thought.


2013 ◽  
Vol 61 (5) ◽  
pp. 378 ◽  
Author(s):  
Stephen H. Kolomyjec ◽  
Tom R. Grant ◽  
Christopher N. Johnson ◽  
David Blair

The platypus (Ornithorhynchus anatinus) has a wide distribution in Australia, encompassing the southern island of Tasmania and a broad latitudinal range of the mainland from the temperate south to the tropical north. We used 12 microsatellite markers from 235 individuals sampled from 13 river systems to examine patterns of genetic differentiation and gene flow throughout the species’ range. Using a Bayesian approach we identified three large-scale groupings that correspond closely to geographically distinct regions of the species’ distribution: the tropical northern mainland, the subtropical and temperate southern mainland, and Tasmania. Six additional clusters were found within the regional groups, three in the northern, two in the southern mainland regions, and the last in Tasmania. These clusters coincided with major river drainages. Genetic differentiation was generally high, with pairwise Fst values ranging from 0.065 to 0.368 for regions and 0.037 to 0.479 for clusters. We found no evidence of contemporary gene flow among the three clusters in the north, but some migration may occur between the larger clusters in the south. Due to the high genetic structuring and lack of gene flow between these three regional populations of the platypus we recommend their treatment as evolutionarily significant units (ESUs) within the platypus species. We have also detailed several smaller management units (MUs) existing within our study area based on subregional clusters and geographically significant features.


2018 ◽  
Author(s):  
Chuan-Chao Wang ◽  
Sabine Reinhold ◽  
Alexey Kalmykov ◽  
Antje Wissgott ◽  
Guido Brandt ◽  
...  

AbstractArchaeogenetic studies have described the formation of Eurasian ‘steppe ancestry’ as a mixture of Eastern and Caucasus hunter-gatherers. However, it remains unclear when and where this ancestry arose and whether it was related to a horizon of cultural innovations in the 4thmillennium BCE that subsequently facilitated the advance of pastoral societies likely linked to the dispersal of Indo-European languages. To address this, we generated genome-wide SNP data from 45 prehistoric individuals along a 3000-year temporal transect in the North Caucasus. We observe a genetic separation between the groups of the Caucasus and those of the adjacent steppe. The Caucasus groups are genetically similar to contemporaneous populations south of it, suggesting that – unlike today – the Caucasus acted as a bridge rather than an insurmountable barrier to human movement. The steppe groups from Yamnaya and subsequent pastoralist cultures show evidence for previously undetected farmer-related ancestry from different contact zones, while Steppe Maykop individuals harbour additional Upper Palaeolithic Siberian and Native American related ancestry.


PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247123
Author(s):  
Navid Yousefi-Mashouf ◽  
Hassan Mehrabani-Yeganeh ◽  
Ardeshir Nejati-Javaremi ◽  
Ernest Bailey ◽  
Jessica L. Petersen

The present research aimed to characterize the Persian Kurdish horse population relative to the Persian Arabian and American Thoroughbred populations using genome-wide SNP data. Fifty-eight Kurdish, 38 Persian Arabian and 83 Thoroughbred horses were genotyped across 670,796 markers. After quality control and pruning to eliminate linkage disequilibrium between loci which resulted in 13,554 SNPs in 52 Kurdish, 24 Persian Arabian and 58 Thoroughbred horses, the Kurdish horses were generally distinguished from the Persian Arabian samples by Principal Component Analyses, cluster analyses and calculation of pairwise FST. Both Persian breeds were discriminated from the Thoroughbred. Pairwise FST between the two Persian samples (0.013) was significantly greater than zero and several fold less than those found between the Thoroughbred and Kurdish (0.052) or Thoroughbred and Persian Arabian (0.057). Cluster analysis assuming three genetic clusters assigned the Kurdish horse and Thoroughbred to distinct clusters (0.942 in cluster 2 and 0.953 in cluster 3 respectively); the Persian Arabian was not in a distinct cluster (0.519 in cluster 1), demonstrating shared ancestry or recent admixture with the Kurdish breed. Diversity as quantified by expected heterozygosity was the highest in the Kurdish horse (0.342), followed by the Persian Arabian (0.328) and the Thoroughbred (0.326). Analysis of Molecular Variance showed that 4.47% of the genetic variation was present among populations (P<0.001). Population-specific inbreeding indices (FIS) were not significantly different from zero in any of the populations. Analysis of individual inbreeding based on runs of homozygosity using a larger SNP set suggested greater diversity in both the Kurdish and Persian Arabian than in the Thoroughbred. These results have implications for developing conservation strategies to achieve sound breeding goals while maintaining genetic diversity.


2019 ◽  
Vol 11 (8) ◽  
pp. 2136-2150 ◽  
Author(s):  
Anna K Hundsdoerfer ◽  
Kyung Min Lee ◽  
Ian J Kitching ◽  
Marko Mutanen

Abstract The interface between populations and evolving young species continues to generate much contemporary debate in systematics depending on the species concept(s) applied but which ultimately reduces to the fundamental question of “when do nondiscrete entities become distinct, mutually exclusive evolutionary units”? Species are perceived as critical biological entities, and the discovery and naming of new species is perceived by many authors as a major research aim for assessing current biodiversity before much of it becomes extinct. However, less attention is given to determining whether these names represent valid biological entities because this is perceived as both a laborious chore and an undesirable research outcome. The charismatic spurge hawkmoths (Hyles euphorbiae complex, HEC) offer an opportunity to study this less fashionable aspect of systematics. To elucidate this intriguing systematic challenge, we analyzed over 10,000 ddRAD single nucleotide polymorphisms from 62 individuals using coalescent-based and population genomic methodology. These genome-wide data reveal a clear overestimation of (sub)species-level diversity and demonstrate that the HEC taxonomy has been seriously oversplit. We conclude that only one valid species name should be retained for the entire HEC, namely Hyles euphorbiae, and we do not recognize any formal subspecies or other taxonomic subdivisions within it. Although the adoption of genetic tools has frequently revealed morphologically cryptic diversity, the converse, taxonomic oversplitting of species, is generally (and wrongly in our opinion) accepted as rare. Furthermore, taxonomic oversplitting is most likely to have taken place in intensively studied popular and charismatic organisms such as the HEC.


2021 ◽  
Vol 9 ◽  
Author(s):  
Sakina Elshibli ◽  
Helena Korpelainen

Medemia argun is a wild, dioecious palm, adapted to the harsh arid environment of the Nubian Desert in Sudan and southern Egypt. There is a concern about its conservation status, since little is known about its distribution, abundance, and genetic variation. M. argun grows on the floodplains of seasonal rivers (wadis). The continuing loss of suitable habitats in the Nubian Desert is threatening the survival of this species. We analyzed the genetic diversity, population genetic structure, and occurrence of M. argun populations to foster the development of conservation strategies for M. argun. Genotyping-by-sequencing (GBS) analyses were performed using a whole-genome profiling service. We found an overall low genetic diversity and moderate genetic structuring based on 40 single-nucleotide polymorphisms (SNPs) and 9,866 SilicoDArT markers. The expected heterozygosity of the total population (HT) equaled 0.036 and 0.127, and genetic differentiation among populations/groups (FST) was 0.052 and 0.092, based on SNP and SilicoDArT markers, respectively. Bayesian clustering analyses defined five genetic clusters that did not display any ancestral gene flow among each other. Based on SilicoDArT markers, the results of the analysis of molecular variance (AMOVA) confirmed the previously observed genetic differentiation among generation groups (23%; p &lt; 0.01). Pairwise FST values indicated a genetic gap between old and young individuals. The observed low genetic diversity and its loss among generation groups, even under the detected high gene flow, show genetically vulnerable M. argun populations in the Nubian Desert in Sudan. To enrich and maintain genetic variability in these populations, conservation plans are required, including collection of seed material from genetically diverse populations and development of ex situ gene banks.


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