scholarly journals Riverscape genomics of cichlid fishes in the lower Congo: Uncovering mechanisms of diversification in an extreme hydrological regime

2021 ◽  
Author(s):  
Naoko Kurata ◽  
Michael Hickerson ◽  
Sandra Hoffberg ◽  
Ned Gardiner ◽  
Melanie L.J. Stiassny ◽  
...  
Keyword(s):  
Gene Flow ◽  
Spatial Scales ◽  
Hydrological Regime ◽  
High Energy ◽  
Ecological Specialization ◽  
Cichlid Fishes ◽  
Heterogeneous Habitats ◽  
Snp Data ◽  
Genome Wide ◽  
Physical Barriers

Rivers provide excellent models to understand how species diversity is generated and maintained across heterogeneous habitats. The lower Congo River (LCR) consists of a dynamic hydroscape exhibiting extraordinary aquatic biodiversity, endemicity, and ecological specialization. Previous studies have suggested that the numerous high-energy rapids throughout the LCR form physical barriers to gene flow, thus facilitating diversification and speciation, and generating ichthyofaunal diversity. However, this hypothesis has not been fully explored using genome-wide SNPs for fish species distributed across the LCR. In this study, we examined four species of lamprologine cichlids endemic to the LCR, of which three are sequentially distributed along the LCR without range overlap. Using genome-wide SNP data, we tested the hypotheses that high-energy rapids serve as physical barriers to gene flow that generate genetic divergence at inter- and intraspecific levels, and that gene flow occurs primarily in a downstream direction. Our results are consistent with the prediction that the rapids sometimes serve to reduce gene flow, but also suggest that at certain temporal and spatial scales, they may also act as promoters of gene flow. Furthermore, we detected both upstream and downstream gene flow between some populations of Lamprologus tigripictilis as well as hybridization between congeneric species. These results suggest that powerful high-energy rapids may therefore provide occasional multidirectional dispersal opportunities for riverine cichlid fishes, highlighting the complexity of factors driving evolutionary processes in the LCR.

scholarly journals Genetic analysis of Sephardic ancestry in the Iberian Peninsula

2018 ◽  
Author(s):  
Miguel Martín Álvarez-Álvarez ◽  
Neil Risch ◽  
Christopher R. Gignoux ◽  
Scott Huntsman ◽  
Elad Ziv ◽  
...  
Keyword(s):  
Gene Flow ◽  
Iberian Peninsula ◽  
Eastern Mediterranean ◽  
Genetic Data ◽  
North African ◽  
Religious Persecution ◽  
South Italy ◽  
Target Populations ◽  
Snp Data ◽  
Genome Wide

AbstractThe Sephardim are a major Jewish ethnic division whose origins can be traced back to the Iberian Peninsula. We used genome-wide SNP data to investigate the degree of Sephardic admixture in seven populations from the Iberian Peninsula and surrounding regions in the aftermath of their religious persecution starting in the late 14th century. To this end, we used Eastern Mediterranean (from South Italy, Greece and Israel) and North African (Tunisian and Moroccan) populations as proxies for the major ancestral components found in the target populations and carried out unlinked- and linked-marker analyses on the available genetic data. We report evidence of Sephardic ancestry in some of our Iberian samples, as well as in North Italy and Tunisia. We find the Sephardic admixture to be more recent relative to the Berber admixture following an out-of-Iberia geographic dispersal, suggesting Sephardic gene flow from Spain outwards. We also report some of the challenges in assigning Sephardic ancestry to potentially admixed individuals due to the lack of a clear genetic signature.

Is Niagara Falls a barrier to gene flow in riverine fishes? A test using genome‐wide SNP data from seven native species

2020 ◽  
Vol 29 (7) ◽  
pp. 1235-1249 ◽  
Author(s):  
Nathan K. Lujan ◽  
Jason T. Weir ◽  
Brice P. Noonan ◽  
Nathan R. Lovejoy ◽  
Nicholas E. Mandrak
Keyword(s):  
Gene Flow ◽  
Native Species ◽  
Niagara Falls ◽  
Snp Data ◽  
Genome Wide

scholarly journals Denisovan Ancestry in East Eurasian and Native American Populations.

2015 ◽  
Author(s):  
Pengfei Qin ◽  
Mark Stoneking
Keyword(s):  
Native American ◽  
Gene Flow ◽  
New Guinea ◽  
Modern Human ◽  
Common Source ◽  
Human Populations ◽  
Snp Data ◽  
Genome Wide ◽  
Or Gene ◽  
The Relationship

Although initial studies suggested that Denisovan ancestry was found only in modern human populations from island Southeast Asia and Oceania, more recent studies have suggested that Denisovan ancestry may be more widespread. However, the geographic extent of Denisovan ancestry has not been determined, and moreover the relationship between the Denisovan ancestry in Oceania and that elsewhere has not been studied. Here we analyze genome-wide SNP data from 2493 individuals from 221 worldwide populations, and show that there is a widespread signal of a very low level of Denisovan ancestry across Eastern Eurasian and Native American (EE/NA) populations. We also verify a higher level of Denisovan ancestry in Oceania than that in EE/NA; the Denisovan ancestry in Oceania is correlated with the amount of New Guinea ancestry, but not the amount of Australian ancestry, indicating that recent gene flow from New Guinea likely accounts for signals of Denisovan ancestry across Oceania. However, Denisovan ancestry in EE/NA populations is equally correlated with their New Guinea or their Australian ancestry, suggesting a common source for the Denisovan ancestry in EE/NA and Oceanian populations. Our results suggest that Denisovan ancestry in EE/NA is derived either from common ancestry with, or gene flow from, the common ancestor of New Guineans and Australians, indicating a more complex history involving East Eurasians and Oceanians than previously suspected.

scholarly journals Genomic analyses suggest strong population connectivity over large spatial scales of the commercially important baitworm, Australonuphis teres (Onuphidae)

2020 ◽  
Vol 71 (11) ◽  
pp. 1549
Author(s):  
Amanda Padovan ◽  
Rowan C. Chick ◽  
Victoria J. Cole ◽  
Ludovic Dutoit ◽  
Patricia A. Hutchings ◽  
...  
Keyword(s):  
Gene Flow ◽  
Spatial Scales ◽  
Population Connectivity ◽  
Eastern Coast ◽  
Marine Biodiversity ◽  
Marine Animals ◽  
Long Distance ◽  
South Wales ◽  
Genome Wide ◽  
Eastern Australia

Barriers to dispersal can disrupt gene flow between populations, resulting in genetically distinct populations. Although many marine animals have potential for long-distance dispersal via a planktonic stage, gene flow among populations separated by large geographic distances is not always evident. Polychaetes are ecologically important and have been used as biological surrogates for marine biodiversity. Some polychaete species are used as bait for recreational fisheries, with this demand supporting commercial fisheries for polychaetes to service the retail bait market. However, despite their ecological and economic importance, very little is known about the life history or population dynamics of polychaetes, and few studies have used genetic or genomic approaches to understand polychaete population connectivity. Here, we investigate the population structure of one commonly collected beachworm species used for bait on the eastern coast of Australia, namely, Australonuphis teres, by using genome-wide single-nucleotide polymorphism data. We sampled A. teres from hierarchical nested spatial scales along 900km of the coast in New South Wales. We identified six genetic groups, but there was no clear geographic pattern of distribution. Our results suggest that there is considerable gene flow among the sampled populations. These high-resolution genomic data support the findings of previous studies, and we infer that oceanographic processes promote genetic exchange among polychaete populations in south-eastern Australia.

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
Keyword(s):  
Phylogenetic Analyses ◽  
Freshwater Mussel ◽  
Conservation Strategies ◽  
Nucleotide Polymorphisms ◽  
Conservation Units ◽  
Genetic Structuring ◽  
The North ◽  
Snp Data ◽  
Genome Wide ◽  
Significant Difference

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.

scholarly journals Genomic variation in the American pika: signatures of geographic isolation and implications for conservation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kelly B. Klingler ◽  
Joshua P. Jahner ◽  
Thomas L. Parchman ◽  
Chris Ray ◽  
Mary M. Peacock
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Sierra Nevada ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Thermal Sensitivity ◽  
Genomic Variation ◽  
Genome Wide ◽  
A Genome ◽  
American Pika

Abstract Background Distributional responses by alpine taxa to repeated, glacial-interglacial cycles throughout the last two million years have significantly influenced the spatial genetic structure of populations. These effects have been exacerbated for the American pika (Ochotona princeps), a small alpine lagomorph constrained by thermal sensitivity and a limited dispersal capacity. As a species of conservation concern, long-term lack of gene flow has important consequences for landscape genetic structure and levels of diversity within populations. Here, we use reduced representation sequencing (ddRADseq) to provide a genome-wide perspective on patterns of genetic variation across pika populations representing distinct subspecies. To investigate how landscape and environmental features shape genetic variation, we collected genetic samples from distinct geographic regions as well as across finer spatial scales in two geographically proximate mountain ranges of eastern Nevada. Results Our genome-wide analyses corroborate range-wide, mitochondrial subspecific designations and reveal pronounced fine-scale population structure between the Ruby Mountains and East Humboldt Range of eastern Nevada. Populations in Nevada were characterized by low genetic diversity (π = 0.0006–0.0009; θW = 0.0005–0.0007) relative to populations in California (π = 0.0014–0.0019; θW = 0.0011–0.0017) and the Rocky Mountains (π = 0.0025–0.0027; θW = 0.0021–0.0024), indicating substantial genetic drift in these isolated populations. Tajima’s D was positive for all sites (D = 0.240–0.811), consistent with recent contraction in population sizes range-wide. Conclusions Substantial influences of geography, elevation and climate variables on genetic differentiation were also detected and may interact with the regional effects of anthropogenic climate change to force the loss of unique genetic lineages through continued population extirpations in the Great Basin and Sierra Nevada.

scholarly journals Genome-wide SNP data unravel the ancestry and signatures of divergent selection in Ghurrah pigs of India

2021 ◽  
pp. 104587
Author(s):  
Arnav Mehrotra ◽  
Bharat Bhushan ◽  
Karthikeyan A ◽  
Akansha Singh ◽  
Snehasmita Panda ◽  
...  
Keyword(s):  
Divergent Selection ◽  
Snp Data ◽  
Genome Wide

scholarly journals Adaptive Divergence under Gene Flow along an Environmental Gradient in Two Coexisting Stickleback Species

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 435
Author(s):  
Thijs M. P. Bal ◽  
Alejandro Llanos-Garrido ◽  
Anurag Chaturvedi ◽  
Io Verdonck ◽  
Bart Hellemans ◽  
...  
Keyword(s):  
Gene Flow ◽  
Brackish Water ◽  
Environmental Gradient ◽  
Spatial Scales ◽  
Morphological Differentiation ◽  
Genotyping By Sequencing ◽  
Adaptive Divergence ◽  
Linkage Groups ◽  
Closely Related Species ◽  
Genomic Patterns

There is a general and solid theoretical framework to explain how the interplay between natural selection and gene flow affects local adaptation. Yet, to what extent coexisting closely related species evolve collectively or show distinctive evolutionary responses remains a fundamental question. To address this, we studied the population genetic structure and morphological differentiation of sympatric three-spined and nine-spined stickleback. We conducted genotyping-by-sequencing and morphological trait characterisation using 24 individuals of each species from four lowland brackish water (LBW), four lowland freshwater (LFW) and three upland freshwater (UFW) sites in Belgium and the Netherlands. This combination of sites allowed us to contrast populations from isolated but environmentally similar locations (LFW vs. UFW), isolated but environmentally heterogeneous locations (LBW vs. UFW), and well-connected but environmentally heterogenous locations (LBW vs. LFW). Overall, both species showed comparable levels of genetic diversity and neutral genetic differentiation. However, for all three spatial scales, signatures of morphological and genomic adaptive divergence were substantially stronger among populations of the three-spined stickleback than among populations of the nine-spined stickleback. Furthermore, most outlier SNPs in the two species were associated with local freshwater sites. The few outlier SNPs that were associated with the split between brackish water and freshwater populations were located on one linkage group in three-spined stickleback and two linkage groups in nine-spined stickleback. We conclude that while both species show congruent evolutionary and genomic patterns of divergent selection, both species differ in the magnitude of their response to selection regardless of the geographical and environmental context.

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