scholarly journals Anthropogenic hybridization at sea: three evolutionary questions relevant to invasive species management

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190547 ◽  
Author(s):  
Frédérique Viard ◽  
Cynthia Riginos ◽  
Nicolas Bierne

Species introductions promote secondary contacts between taxa with long histories of allopatric divergence. Anthropogenic contact zones thus offer valuable contrasts to speciation studies in natural systems where past spatial isolations may have been brief or intermittent. Investigations of anthropogenic hybridization are rare for marine animals, which have high fecundity and high dispersal ability, characteristics that contrast to most terrestrial animals. Genomic studies indicate that gene flow can still occur after millions of years of divergence, as illustrated by invasive mussels and tunicates. In this context, we highlight three issues: (i) the effects of high propagule pressure and demographic asymmetries on introgression directionality, (ii) the role of hybridization in preventing introduced species spread, and (iii) the importance of postzygotic barriers in maintaining reproductive isolation. Anthropogenic contact zones offer evolutionary biologists unprecedented large scale hybridization experiments. In addition to breaking the highly effective reproductive isolating barrier of spatial segregation, they allow researchers to explore unusual demographic contexts with strong asymmetries. The outcomes are diverse, from introgression swamping to strong barriers to gene flow, and lead to local containment or widespread invasion. These outcomes should not be neglected in management policies of marine invasive species. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers’.

2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Akiko Kyuno ◽  
Mifue Shintaku ◽  
Yuko Fujita ◽  
Hiroto Matsumoto ◽  
Motoo Utsumi ◽  
...  

We sequenced the mitochondrial ND4 gene to elucidate the evolutionary processes ofBathymodiolusmussels and mytilid relatives. Mussels of the subfamily Bathymodiolinae from vents and seeps belonged to 3 groups and mytilid relatives from sunken wood and whale carcasses assumed the outgroup positions to bathymodioline mussels. Shallow water mytilid mussels were positioned more distantly relative to the vent/seep mussels, indicating an evolutionary transition from shallow to deep sea via sunken wood and whale carcasses.Bathymodiolus platifronsis distributed in the seeps and vents, which are approximately 1500 km away. There was no significant genetic differentiation between the populations. There existed high gene flow betweenB. septemdierumandB. breviorand low but not negligible gene flow betweenB. marisindicusandB. septemdierumorB. brevior, although their habitats are 5000–10 000 km away. These indicate a high adaptability to the abyssal environments and a high dispersal ability ofBathymodiolusmussels.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Quiterie Haenel ◽  
Krista B. Oke ◽  
Telma G. Laurentino ◽  
Andrew P. Hendry ◽  
Daniel Berner

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.


2020 ◽  
Author(s):  
Quiterie Haenel ◽  
Krista B. Oke ◽  
Telma G. Laurentino ◽  
Andrew P. Hendry ◽  
Daniel Berner

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 population pair adapted to contiguous, ecologically different lake and stream habitats. Dense clinal whole-genome sequence data reveal numerous regions 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 co-localizes with the habitat transition. Simulations confirm that such strong reproductive isolation can be maintained by polygenic selection despite high dispersal and small per-locus selection coefficients. Finally, comparing samples from the cline center 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.


2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters

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.


2014 ◽  
Author(s):  
Tiago Paixão ◽  
Kevin E. Bassler ◽  
Ricardo B. R. Azevedo

The Dobzhansky-Muller model posits that incompatibilities between alleles at different loci cause speciation. However, it is known that if the alleles involved in a Dobzhansky-Muller incompatibility (DMI) between two loci are neutral, the resulting reproductive isolation cannot be maintained in the presence of either mutation or gene flow. Here we show that speciation can emerge through the collective effects of multiple neutral DMIs that cannot, individually, cause speciation-a mechanism we call emergent speciation. We investigate emergent speciation using models of haploid holey adaptive landscapes-neutral networks-with recombination. We find that certain combinations of multiple neutral DMIs can lead to speciation. Furthermore, emergent speciation is a robust mechanism that can occur in the presence of migration, and of deviations from the assumptions of the neutral network model. Strong recombination and complex interactions between the DMI loci facilitate emergent speciation. These conditions are likely to occur in nature. We conclude that the interaction between DMIs may cause speciation.


2018 ◽  
Vol 106 (4) ◽  
pp. 1349-1362 ◽  
Author(s):  
Noelle G. Beckman ◽  
James M. Bullock ◽  
Roberto Salguero-Gómez

Author(s):  
Jeanine Vélez-Gavilán

Abstract Desmodium cajanifolium is a perennial shrub considered as invasive in Hawaii, USA, by Frohlich and Lau (2012), who reported it as a weedy species naturalised along roadsides, open forests and secondary vegetation on the Big Island and Kaua'i. At the same time, Benitez et al. (2012) report D. cajanifolium as a species that is rarely found along roadsides and in forests in Hawaii. D. cajanifolium is not listed as an invasive species on Pacific Islands Ecosystems at Risk (PIER, 2020). No details about its effects over other species or habitats are given.Desmodium cajanifolium is listed as potentially invasive in Cuba, being classified as a species with a tendency to proliferate in some areas and producing vast amounts of diaspores with a high dispersal capacity (Oviedo Prieto et al., 2012). It is considered as uncommon in parts of its native distribution (Flora of Nicaragua, 2020) and as scattered throughout its range (Flora of Panama, 2020).


Sign in / Sign up

Export Citation Format

Share Document