Systematics, reproductive isolation and species boundaries in monogonont rotifers

1989 ◽  
pp. 299-310 ◽  
Author(s):  
Terry W. Snell
Keyword(s):  
Reproductive Isolation ◽  
Species Boundaries ◽  
Monogonont Rotifers

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

scholarly journals Genome reorganization in F 1 hybrids uncovers the role of retrotransposons in reproductive isolation

2015 ◽  
Vol 282 (1804) ◽  
pp. 20142874 ◽  
Author(s):  
Natacha Senerchia ◽  
François Felber ◽  
Christian Parisod
Keyword(s):  
Reproductive Isolation ◽  
Long Terminal Repeat Retrotransposons ◽  
Plant Genome ◽  
Species Boundaries ◽  
Key To Species ◽  
Differential Survival ◽  
Genome Reorganization ◽  
Genome Wide ◽  
New Interactions

Interspecific hybridization leads to new interactions among divergent genomes, revealing the nature of genetic incompatibilities having accumulated during and after the origin of species. Conflicts associated with misregulation of transposable elements (TEs) in hybrids expectedly result in their activation and genome-wide changes that may be key to species boundaries. Repetitive genomes of wild wheats have diverged under differential dynamics of specific long terminal repeat retrotransposons (LTR-RTs), offering unparalleled opportunities to address the underpinnings of plant genome reorganization by selfish sequences. Using reciprocal F 1 hybrids between three Aegilops species, restructuring and epigenetic repatterning was assessed at random and LTR-RT sequences with amplified fragment length polymorphism and sequence-specific amplified polymorphisms as well as their methylation-sensitive counterparts, respectively. Asymmetrical reorganization of LTR-RT families predicted to cause conflicting interactions matched differential survival of F 1 hybrids. Consistent with the genome shock model, increasing divergence of merged LTR-RTs yielded higher levels of changes in corresponding genome fractions and lead to repeated reorganization of LTR-RT sequences in F 1 hybrids. Such non-random reorganization of hybrid genomes is coherent with the necessary repression of incompatible TE loci in support of hybrid viability and indicates that TE-driven genomic conflicts may represent an overlooked factor supporting reproductive isolation.

scholarly journals Model-Based Species Delimitation: Are Coalescent Species Reproductively Isolated?

2019 ◽  
Vol 69 (4) ◽  
pp. 708-721 ◽  
Author(s):  
Luke C Campillo ◽  
Anthony J Barley ◽  
Robert C Thomson
Keyword(s):  
Reproductive Isolation ◽  
Dna Sequence ◽  
Sequence Data ◽  
Species Recognition ◽  
Species Boundaries ◽  
Simultaneous Estimation ◽  
Dna Sequence Data ◽  
Multispecies Coalescent ◽  
Species Pairs ◽  
History Of

Abstract A large and growing fraction of systematists define species as independently evolving lineages that may be recognized by analyzing the population genetic history of alleles sampled from individuals belonging to those species. This has motivated the development of increasingly sophisticated statistical models rooted in the multispecies coalescent process. Specifically, these models allow for simultaneous estimation of the number of species present in a sample of individuals and the phylogenetic history of those species using only DNA sequence data from independent loci. These methods hold extraordinary promise for increasing the efficiency of species discovery but require extensive validation to ensure that they are accurate and precise. Whether the species identified by these methods correspond to the species that would be recognized by alternative species recognition criteria (such as measurements of reproductive isolation) is currently an open question and a subject of vigorous debate. Here, we perform an empirical test of these methods by making use of a classic model system in the history of speciation research, flies of the genus Drosophila. Specifically, we use the uniquely comprehensive data on reproductive isolation that is available for this system, along with DNA sequence data, to ask whether Drosophila species inferred under the multispecies coalescent model correspond to those recognized by many decades of speciation research. We found that coalescent based and reproductive isolation-based methods of inferring species boundaries are concordant for 77% of the species pairs. We explore and discuss potential explanations for these discrepancies. We also found that the amount of prezygotic isolation between two species is a strong predictor of the posterior probability of species boundaries based on DNA sequence data, regardless of whether the species pairs are sympatrically or allopatrically distributed. [BPP; Drosophila speciation; genetic distance; multispecies coalescent.]

scholarly journals The importance of intrinsic postzygotic barriers throughout the speciation process

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190533 ◽  
Author(s):  
Jenn M. Coughlan ◽  
Daniel R. Matute
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Rapid Evolution ◽  
Theoretical Work ◽  
Sympatric Species ◽  
Species Boundaries ◽  
Biological Models ◽  
Speciation Process ◽  
Species Pairs ◽  
Postzygotic Barriers

Intrinsic postzygotic barriers can play an important and multifaceted role in speciation, but their contribution is often thought to be reserved to the final stages of the speciation process. Here, we review how intrinsic postzygotic barriers can contribute to speciation, and how this role may change through time. We outline three major contributions of intrinsic postzygotic barriers to speciation. (i) reduction of gene flow : intrinsic postzygotic barriers can effectively reduce gene exchange between sympatric species pairs. We discuss the factors that influence how effective incompatibilities are in limiting gene flow. (ii) early onset of species boundaries via rapid evolution : intrinsic postzygotic barriers can evolve between recently diverged populations or incipient species, thereby influencing speciation relatively early in the process. We discuss why the early origination of incompatibilities is expected under some biological models, and detail how other (and often less obvious) incompatibilities may also serve as important barriers early on in speciation. (iii) reinforcement : intrinsic postzygotic barriers can promote the evolution of subsequent reproductive isolation through processes such as reinforcement, even between relatively recently diverged species pairs. We incorporate classic and recent empirical and theoretical work to explore these three facets of intrinsic postzygotic barriers, and provide our thoughts on recent challenges and areas in the field in which progress can be made. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers’.

scholarly journals Asymmetries of reproductive isolation are reflected in directionalities of hybridization: integrative evidence on the complexity of species boundaries

2020 ◽  
Vol 229 (3) ◽  
pp. 1795-1809
Author(s):  
Barbara Keller ◽  
Rita Ganz ◽  
Emiliano Mora‐Carrera ◽  
Michael D. Nowak ◽  
Spyros Theodoridis ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Species Boundaries

scholarly journals Model-based species delimitation: are coalescent species reproductively isolated?

2019 ◽  
Author(s):  
Luke C. Campillo ◽  
Anthony J. Barley ◽  
Robert C. Thomson
Keyword(s):  
Reproductive Isolation ◽  
Dna Sequence ◽  
Sequence Data ◽  
Species Recognition ◽  
Species Boundaries ◽  
Simultaneous Estimation ◽  
Dna Sequence Data ◽  
Multispecies Coalescent ◽  
Species Pairs ◽  
History Of

ABSTRACTA large and growing fraction of systematists define species as independently evolving lineages that may be recognized by analyzing the population genetic history of alleles sampled from individuals belonging to those species. This has motivated the development of increasingly sophisticated statistical models rooted in the multispecies coalescent process. Specifically, these models allow for simultaneous estimation of the number of species present in a sample of individuals and the phylogenetic history of those species using only DNA sequence data from independent loci. These methods hold extraordinary promise for increasing the efficiency of species discovery, but require extensive validation to ensure that they are accurate and precise. Whether the species identified by these methods correspond to the species that would be recognized by alternative species recognition criteria (such as measurements of reproductive isolation) is currently an open question, and a subject of vigorous debate. Here we perform an empirical test of these methods by making use of a classic model system in the history of speciation research, flies of the genus Drosophila. Specifically, we use the uniquely comprehensive data on reproductive isolation that is available for this system, along with DNA sequence data, to ask whether Drosophila species inferred under the multispecies coalescent model correspond to those recognized by many decades of speciation research. We found that coalescent based and reproductive isolation based methods of inferring species boundaries are concordant for 77% of the species pairs. We explore and discuss potential explanations for these discrepancies. We also found that the amount of prezygotic isolation between two species is a strong predictor of the posterior probability of species boundaries based on DNA sequence data, regardless of whether the species pairs are sympatrically or allopatrically distributed.

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