scholarly journals Cryptic species diversity and reproductive isolation among sympatric lineages of Strongylocentrotus sea urchins in the northwest Atlantic

FACETS ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 61-78 ◽  
Author(s):  
Jason A. Addison ◽  
Jin-Hong Kim
Keyword(s):  
Reproductive Isolation ◽  
Cryptic Species ◽  
Sea Urchins ◽  
Incomplete Lineage Sorting ◽  
Strongylocentrotus Droebachiensis ◽  
Population Substructure ◽  
Nucleotide Polymorphisms ◽  
Lineage Sorting ◽  
Genetic Studies ◽  
Coi Sequences

Distinguishing between intra- and inter-specific variation in genetic studies is critical to understanding evolution because the mechanisms driving change among populations are expected to be different than those that shape reproductive isolation among lineages. Genetic studies of north Atlantic green sea urchins Strongylocentrotus droebachiensis (Müller, 1776) have detected significant population substructure and asymmetric gene flow from Europe to Atlantic Canada and interspecific hybridization between S. droebachiensis and Strongylocentrotus pallidus (Sars, 1871). However, combined with patterns of divergence at mtDNA sequences, morphological divergence at gamete traits suggests that the European and North American lineages of S. droebachiensis may be cryptic species. Here, we use a combination of cytochrome c oxidase subunit I ( COI) sequences and single nucleotide polymorphisms (SNPs) to test for cryptic species within Strongylocentrotus sea urchins and hybrids between S. droebachiensis and S. pallidus populations. We detect striking patterns of habitat and reproductive isolation between two S. droebachiensis lineages, with offshore deep-water collections consisting of S. pallidus in addition to a cryptic lineage sharing genetic similarity with previously published sequences from eastern Atlantic S. droebachiensis. We detected only limited hybridization among all three lineages of sea urchins, suggesting that shared genetic differences previously reported may be a result of historical introgression or incomplete lineage sorting.

scholarly journals Incomplete lineage sorting and ancient admixture, and speciation without morphological change in ghost-worm cryptic species

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10896
Author(s):  
José Cerca ◽  
Angel G. Rivera-Colón ◽  
Mafalda S. Ferreira ◽  
Mark Ravinet ◽  
Michael D. Nowak ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Cryptic Species ◽  
Species Complex ◽  
Population Genomics ◽  
Incomplete Lineage Sorting ◽  
Morphological Evolution ◽  
Population Level ◽  
Similar Species ◽  
Lineage Sorting ◽  
Amplification Method

Morphologically similar species, that is cryptic species, may be similar or quasi-similar owing to the deceleration of morphological evolution and stasis. While the factors underlying the deceleration of morphological evolution or stasis in cryptic species remain unknown, decades of research in the field of paleontology on punctuated equilibrium have originated clear hypotheses. Species are expected to remain morphologically identical in scenarios of shared genetic variation, such as hybridization and incomplete lineage sorting, or in scenarios where bottlenecks reduce genetic variation and constrain the evolution of morphology. Here, focusing on three morphologically similar Stygocapitella species, we employ a whole-genome amplification method (WGA) coupled with double-digestion restriction-site associated DNA sequencing (ddRAD) to reconstruct the evolutionary history of the species complex. We explore population structure, use population-level statistics to determine the degree of connectivity between populations and species, and determine the most likely demographic scenarios which generally reject for recent hybridization. We find that the combination of WGA and ddRAD allowed us to obtain genomic-level data from microscopic eukaryotes (∼1 millimetre) opening up opportunities for those working with population genomics and phylogenomics in such taxa. The three species share genetic variance, likely from incomplete lineage sorting and ancient admixture. We speculate that the degree of shared variation might underlie morphological similarity in the Atlantic species complex.

scholarly journals Genomic insights into adaptive divergence and speciation among malaria vectors of the Anopheles nili group

2016 ◽  
Author(s):  
Caroline Fouet ◽  
Colince Kamdem ◽  
Stephanie Gamez ◽  
Bradley J. White
Keyword(s):  
Population Structure ◽  
Large Scale ◽  
Incomplete Lineage Sorting ◽  
Snp Markers ◽  
Malaria Vectors ◽  
Adaptive Divergence ◽  
Nucleotide Polymorphisms ◽  
Lineage Sorting ◽  
Interspecific Gene Flow ◽  
Scale Control

AbstractOngoing speciation in most African malaria vectors gives rise to cryptic populations, which differ remarkably in their behaviour, ecology and capacity to vector malaria parasites. Understanding the population structure and the drivers of genetic differentiation among mosquitoes is critical for effective disease control because heterogeneity within species contribute to variability in malaria cases and allow fractions of vector populations to escape control efforts. To examine the population structure and the potential impacts of recent large-scale control interventions, we have investigated the genomic patterns of differentiation in mosquitoes belonging to the Anopheles nili group, a large taxonomic group that diverged ∼3-Myr ago. Using 4343 single nucleotide polymorphisms (SNPs), we detected strong population structure characterized by high FST values between multiple divergent populations adapted to different habitats within the Central African rainforest. Delineating the cryptic species within the Anopheles nili group is challenging due to incongruence between morphology, ribosomal DNA and SNP markers consistent with incomplete lineage sorting and/or interspecific gene flow. A very high proportion of loci are fixed (FST = 1) within the genome of putative species, which suggests that ecological and/or reproductive barriers are maintained by strong selection on a substantial number of genes.

scholarly journals Multiple data revealed two new species of the Asian horned toad Megophrys Kuhl & Van Hasselt, 1822 (Anura, Megophryidae) from the eastern corner of the Himalayas

ZooKeys ◽  
2020 ◽  
Vol 977 ◽  
pp. 101-161
Author(s):  
Shengchao Shi ◽  
Meihua Zhang ◽  
Feng Xie ◽  
Jianping Jiang ◽  
Wulin Liu ◽  
...  
Keyword(s):  
Cryptic Species ◽  
Evolutionary History ◽  
Molecular Phylogenetics ◽  
Nuclear Dna ◽  
Incomplete Lineage Sorting ◽  
High Elevation ◽  
Climatic Changes ◽  
Lineage Sorting ◽  
Multiple Data ◽  
Tibet Autonomous Region

Multiple disciplines can help to discover cryptic species and resolve taxonomic confusions. The Asian horned toad genus Megophryssensu lato as a diverse group was proposed to contain dozens of cryptic species. Based on molecular phylogenetics, morphology, osteology, and bioacoustics data, the species profiles of Megophrys toads in the eastern corner of Himalayas in Medog County, Tibet Autonomous Region, China was investigated. The results indicated that this small area harbored at least four Megophrys species, i.e., M. medogensis, M. pachyproctus, Megophrys zhouisp. nov., and Megophrys yeaesp. nov., the latter two being described in this study. Additionally, the mitochondrial DNA trees nested the low-middle-elevation and high-elevation groups of M. medogensis into a monophyletic group, being in discordance with the paraphyletic relationship between them revealed in the nuclear DNA trees. The findings highlighted the underestimated biodiversity in Himalayas, and further indicated that the Megophrys toads here have been probably experienced complicated evolutionary history, for example, introgression between clades or incomplete lineage sorting and niche divergences in microhabitats. Anyway, it is urgent for us to explore the problems because these toads are suffering from increasing threats from human activities and climatic changes.

scholarly journals A next generation approach to species delimitation reveals the role of hybridization in a cryptic species complex of corals

2019 ◽  
Author(s):  
Andrea M. Quattrini ◽  
Tiana Wu ◽  
Keryea Soong ◽  
Ming-Shiou Jeng ◽  
Yehuda Benayahu ◽  
...  
Keyword(s):  
Cryptic Species ◽  
Species Delimitation ◽  
Incomplete Lineage Sorting ◽  
Dna Barcode ◽  
Species Boundaries ◽  
Future Research ◽  
Species Trees ◽  
Lineage Sorting ◽  
Evolutionary Diversification

AbstractBackgroundOur ability to investigate processes shaping the evolutionary diversification of corals (Cnidaria: Anthozoa) is limited by a lack of understanding of species boundaries. Discerning species has been challenging due to a multitude of factors, including homoplasious and plastic morphological characters and the use of molecular markers that are either not informative or have not completely sorted. Hybridization can also blur species boundaries by leading to incongruence between morphology and genetics. We used traditional DNA barcoding and restriction-site associated DNA sequencing combined with coalescence-based and allele-frequency methods to elucidate species boundaries and simultaneously examine the potential role of hybridization in a speciose genus of octocoral, Sinularia.ResultsSpecies delimitations using two widely used DNA barcode markers, mtMutS and 28S rDNA, were incongruent with one another and with the morphospecies identifications, likely due to incomplete lineage sorting. In contrast, 12 of the 15 morphospecies examined formed well-supported monophyletic clades in both concatenated RAxML phylogenies and SNAPP species trees of >6,000 RADSeq loci. DAPC and Structure analyses also supported morphospecies assignments, but indicated the potential for two additional cryptic species. Three morphologically distinct species pairs could not, however, be distinguished genetically. ABBA-BABA tests demonstrated significant admixture between some of those species, suggesting that hybridization may confound species delimitation in Sinularia.ConclusionsA genomic approach can help to guide species delimitation while simultaneously elucidating the processes generating diversity in corals. Results support the hypothesis that hybridization is an important mechanism in the evolution of Anthozoa, including octocorals, and future research should examine the contribution of this mechanism in generating diversity across the coral tree of life.

scholarly journals DNA barcoding mosquitoes: advice for potential prospectors

Parasitology ◽  
2018 ◽  
Vol 145 (5) ◽  
pp. 622-633 ◽  
Author(s):  
NIGEL W. BEEBE
Keyword(s):  
Incomplete Lineage Sorting ◽  
Mosquito Species ◽  
Dna Barcode ◽  
Nuclear Marker ◽  
Lineage Sorting ◽  
Mtdna Sequences ◽  
Closely Related Species ◽  
Pros And Cons ◽  
Species Groups ◽  
Coi Sequences

SUMMARYMosquitoes’ importance as vectors of pathogens that drive disease underscores the importance of precise and comparable methods of taxa identification among their species. While several molecular targets have been used to study mosquitoes since the initiation of PCR in the 1980s, its application to mosquito identification took off in the early 1990s. This review follows the research's recent journey into the use of mitochondrial DNA (mtDNA) cytochrome oxidase 1 (COI or COX1) as a DNA barcode target for mosquito species identification – a target whose utility for discriminating mosquitoes is now escalating. The pros and cons of using a mitochondrial genome target are discussed with a broad sweep of the mosquito literature suggesting that nuclear introgressions of mtDNA sequences appear to be uncommon and that the COI works well for distantly related taxa and shows encouraging utility in discriminating more closely related species such as cryptic/sibling species groups. However, the utility of COI in discriminating some closely related groups can be problematic and investigators are advised to proceed with caution as problems with incomplete lineage sorting and introgression events can result in indistinguishable COI sequences appearing in reproductively independent populations. In these – if not all – cases, it is advisable to run a nuclear marker alongside the mtDNA and thus the utility of the ribosomal DNA – and in particular the internal transcribed spacer 2 – is also briefly discussed as a useful counterpoint to the COI.

scholarly journals Speciation genes are more likely to have discordant gene trees

2018 ◽  
Author(s):  
Richard J. Wang ◽  
Matthew W. Hahn
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Incomplete Lineage Sorting ◽  
Gene Trees ◽  
Species Trees ◽  
Species Relationships ◽  
Lineage Sorting ◽  
Epistatic Interactions ◽  
Speciation Event ◽  
History Of

AbstractSpeciation genes are responsible for reproductive isolation between species. By directly participating in the process of speciation, the genealogies of isolating loci have been thought to more faithfully represent species trees. The unique properties of speciation genes may provide valuable evolutionary insights and help determine the true history of species divergence. Here, we formally analyze whether genealogies from loci participating in Dobzhansky-Muller (DM) incompatibilities are more likely to be concordant with the species tree under incomplete lineage sorting (ILS). Individual loci differ stochastically from the true history of divergence with a predictable frequency due to ILS, and these expectations—combined with the DM model of intrinsic reproductive isolation from epistatic interactions—can be used to examine the probability of concordance at isolating loci. Contrary to existing verbal models, we find that reproductively isolating loci that follow the DM model are often more likely to have discordant gene trees. These results are dependent on the pattern of isolation observed between three species, the time between speciation events, and the time since the last speciation event. Results supporting a higher probability of discordance are found for both derived-derived and derived-ancestral DM pairs, and regardless of whether incompatibilities are allowed or prohibited from segregating in the same population. Our overall results suggest that DM loci are unlikely to be especially useful for reconstructing species relationships, even in the presence of gene flow between incipient species, and may in fact be positively misleading.

scholarly journals The Perfect Storm: Gene Tree Estimation Error, Incomplete Lineage Sorting, and Ancient Gene Flow Explain the Most Recalcitrant Ancient Angiosperm Clade, Malpighiales

2020 ◽  
Author(s):  
Liming Cai ◽  
Zhenxiang Xi ◽  
Emily Moriarty Lemmon ◽  
Alan R Lemmon ◽  
Austin Mast ◽  
...  
Keyword(s):  
Gene Flow ◽  
Incomplete Lineage Sorting ◽  
Estimation Error ◽  
Gene Tree ◽  
Species Tree ◽  
Flowering Plant ◽  
Estimation Methods ◽  
Lineage Sorting ◽  
Tree Estimation ◽  
Perfect Storm

Abstract The genomic revolution offers renewed hope of resolving rapid radiations in the Tree of Life. The development of the multispecies coalescent (MSC) model and improved gene tree estimation methods can better accommodate gene tree heterogeneity caused by incomplete lineage sorting (ILS) and gene tree estimation error stemming from the short internal branches. However, the relative influence of these factors in species tree inference is not well understood. Using anchored hybrid enrichment, we generated a data set including 423 single-copy loci from 64 taxa representing 39 families to infer the species tree of the flowering plant order Malpighiales. This order includes nine of the top ten most unstable nodes in angiosperms, which have been hypothesized to arise from the rapid radiation during the Cretaceous. Here, we show that coalescent-based methods do not resolve the backbone of Malpighiales and concatenation methods yield inconsistent estimations, providing evidence that gene tree heterogeneity is high in this clade. Despite high levels of ILS and gene tree estimation error, our simulations demonstrate that these two factors alone are insufficient to explain the lack of resolution in this order. To explore this further, we examined triplet frequencies among empirical gene trees and discovered some of them deviated significantly from those attributed to ILS and estimation error, suggesting gene flow as an additional and previously unappreciated phenomenon promoting gene tree variation in Malpighiales. Finally, we applied a novel method to quantify the relative contribution of these three primary sources of gene tree heterogeneity and demonstrated that ILS, gene tree estimation error, and gene flow contributed to 10.0%, 34.8%, and 21.4% of the variation, respectively. Together, our results suggest that a perfect storm of factors likely influence this lack of resolution, and further indicate that recalcitrant phylogenetic relationships like the backbone of Malpighiales may be better represented as phylogenetic networks. Thus, reducing such groups solely to existing models that adhere strictly to bifurcating trees greatly oversimplifies reality, and obscures our ability to more clearly discern the process of evolution.

scholarly journals Morphological, Ecological, and Molecular Divergence of Conogethes pinicolalis from C. punctiferalis (Lepidoptera: Crambidae)

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 455
Author(s):  
Na Ra Jeong ◽  
Min Jee Kim ◽  
Sung-Soo Kim ◽  
Sei-Woong Choi ◽  
Iksoo Kim
Keyword(s):  
Phylogenetic Analysis ◽  
First Generation ◽  
Incomplete Lineage Sorting ◽  
Divergence Time ◽  
Sequence Divergence ◽  
Lineage Sorting ◽  
Mitochondrial Coi ◽  
Feeding Type ◽  
Pine Trees ◽  
Yellow Peach Moth

Conogethes pinicolalis has long been considered as a Pinaceae-feeding type of the yellow peach moth, C. punctiferalis, in Korea. In this study, the divergence of C. pinicolalis from the fruit-feeding moth C. punctiferalis was analyzed in terms of morphology, ecology, and genetics. C. pinicolalis differs from C. punctiferalis in several morphological features. Through field observation, we confirmed that pine trees are the host plants for the first generation of C. pinicolalis larvae, in contrast to fruit-feeding C. punctiferalis larvae. We successfully reared C. pinicolalis larvae to adults by providing them pine needles as a diet. From a genetic perspective, the sequences of mitochondrial COI of these two species substantially diverged by an average of 5.46%; moreover, phylogenetic analysis clearly assigned each species to an independent clade. On the other hand, nuclear EF1α showed a lower sequence divergence (2.10%) than COI. Overall, EF1α-based phylogenetic analysis confirmed each species as an independent clade, but a few haplotypes of EF1α indicated incomplete lineage sorting between these two species. In conclusion, our results demonstrate that C. pinicolalis is an independent species according to general taxonomic criteria; however, analysis of the EF1α sequence revealed a short divergence time.

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