Demographic history, geographical distribution and reproductive isolation of distinct lineages of blue rockfish (Sebastes mystinus), a marine fish with a high dispersal potential

2009 ◽  
Vol 22 (7) ◽  
pp. 1471-1486 ◽  
Author(s):  
M. O. BURFORD
Keyword(s):  
Reproductive Isolation ◽  
Geographical Distribution ◽  
Marine Fish ◽  
Demographic History ◽  
High Dispersal ◽  
Dispersal Potential ◽  
Sebastes Mystinus

scholarly journals Ancestral and neo-sex chromosomes contribute to population divergence in a dioecious plant

2019 ◽  
Author(s):  
Felix E.G. Beaudry ◽  
Spencer C.H. Barrett ◽  
Stephen I. Wright
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Demographic History ◽  
Population Divergence ◽  
Effective Population ◽  
Dioecious Plant ◽  
Fusion Event ◽  
Contemporary Gene Flow

ABSTRACTEmpirical evidence from several animal groups suggests that sex chromosomes may disproportionately contribute to reproductive isolation. This occurs particularly when sex chromosomes are associated with turnover of sex determination systems resulting from structural rearrangements to the sex chromosomes. We investigated these predictions in the dioecious plant Rumex hastatulus, which is comprised of populations of two sex chromosome cytotypes. Using population genomic analyses, we investigated the demographic history of R. hastatulus and explored the contributions of ancestral and neo-sex chromosomes to population genetic divergence. Our study revealed that the cytotypes represented genetically divergent populations with evidence for historical but not contemporary gene flow between them. In agreement with classical predictions, we found that the ancestral X chromosome was disproportionately divergent compared with the rest of the genome. Excess differentiation was also observed on the Y chromosome, even when using measures of differentiation that control for differences in effective population size. Our estimates of the timing of the origin of the neo-sex chromosomes in R. hastatulus are coincident with cessation of gene flow, suggesting that the chromosomal fusion event that gave rise to the origin of the XYY cytotype may have also been a key driver of reproductive isolation.

scholarly journals The evolution of strong reproductive isolation between sympatric intertidal snails

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190545 ◽  
Author(s):  
Sean Stankowski ◽  
Anja M. Westram ◽  
Zuzanna B. Zagrodzka ◽  
Isobel Eyres ◽  
Thomas Broquet ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Biological Diversity ◽  
Demographic History ◽  
Egg Laying ◽  
Female Reproduction ◽  
Open Questions ◽  
Geographical Separation ◽  
Short Period ◽  
Littorina Arcana ◽  
Subsequent Effect

The evolution of strong reproductive isolation (RI) is fundamental to the origins and maintenance of biological diversity, especially in situations where geographical distributions of taxa broadly overlap. But what is the history behind strong barriers currently acting in sympatry? Using whole-genome sequencing and single nucleotide polymorphism genotyping, we inferred (i) the evolutionary relationships, (ii) the strength of RI, and (iii) the demographic history of divergence between two broadly sympatric taxa of intertidal snail. Despite being cryptic, based on external morphology, Littorina arcana and Littorina saxatilis differ in their mode of female reproduction (egg-laying versus brooding), which may generate a strong post-zygotic barrier. We show that egg-laying and brooding snails are closely related, but genetically distinct. Genotyping of 3092 snails from three locations failed to recover any recent hybrid or backcrossed individuals, confirming that RI is strong. There was, however, evidence for a very low level of asymmetrical introgression, suggesting that isolation remains incomplete. The presence of strong, asymmetrical RI was further supported by demographic analysis of these populations. Although the taxa are currently broadly sympatric, demographic modelling suggests that they initially diverged during a short period of geographical separation involving very low gene flow. Our study suggests that some geographical separation may kick-start the evolution of strong RI, facilitating subsequent coexistence of taxa in sympatry. The strength of RI needed to achieve sympatry and the subsequent effect of sympatry on RI remain open questions. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.

Glugea vincentiae. [Descriptions of Fungi and Bacteria].

2019 ◽  
Author(s):  
D. W. Minter
Keyword(s):  
Geographical Distribution ◽  
Marine Fish ◽  
The Family

Abstract This article describes the morphology, morphometrics, and geographical distribution of the parasite Glugea vincentiae infecting marine fish of the family Apogonidae (cardinal fish) off the coast of southern Australia. This parasite is only endemic to Australia.

The geographic scale of speciation in a marine snail with high dispersal potential

2011 ◽  
Vol 38 (6) ◽  
pp. 1016-1032 ◽  
Author(s):  
Martine Claremont ◽  
Suzanne T. Williams ◽  
Timothy G. Barraclough ◽  
David G. Reid
Keyword(s):  
Geographic Scale ◽  
Marine Snail ◽  
High Dispersal ◽  
Dispersal Potential

scholarly journals Thermal adaptation rather than demographic history drives genetic structure inferred by copy number variants in a marine fish

2021 ◽  
Vol 30 (7) ◽  
pp. 1624-1641
Author(s):  
Hugo Cayuela ◽  
Yann Dorant ◽  
Claire Mérot ◽  
Martin Laporte ◽  
Eric Normandeau ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Marine Fish ◽  
Copy Number ◽  
Demographic History ◽  
Copy Number Variants ◽  
Thermal Adaptation

scholarly journals Clinal genomic analysis reveals strong reproductive isolation across a steep habitat transition in stickleback fish

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Quiterie Haenel ◽  
Krista B. Oke ◽  
Telma G. Laurentino ◽  
Andrew P. Hendry ◽  
Daniel Berner
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sequence Data ◽  
Genomic Analysis ◽  
Whole Genome Sequence ◽  
Adaptive Divergence ◽  
Entire Genome ◽  
High Dispersal ◽  
A Genome ◽  
Habitat Transition

AbstractHow ecological divergence causes strong reproductive isolation between populations in close geographic contact remains poorly understood at the genomic level. We here study this question in a stickleback fish population pair adapted to contiguous, ecologically different lake and stream habitats. Clinal whole-genome sequence data reveal numerous genome regions (nearly) fixed for alternative alleles over a distance of just a few hundred meters. This strong polygenic adaptive divergence must constitute a genome-wide barrier to gene flow because a steep cline in allele frequencies is observed across the entire genome, and because the cline center closely matches the habitat transition. Simulations confirm that such strong divergence can be maintained by polygenic selection despite high dispersal and small per-locus selection coefficients. Finally, comparing samples from near the habitat transition before and after an unusual ecological perturbation demonstrates the fragility of the balance between gene flow and selection. Overall, our study highlights the efficacy of divergent selection in maintaining reproductive isolation without physical isolation, and the analytical power of studying speciation at a fine eco-geographic and genomic scale.

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