RECENT, ALLOPATRIC, HOMOPLOID HYBRID SPECIATION: THE ORIGIN OF SENECIO SQUALIDUS (ASTERACEAE) IN THE BRITISH ISLES FROM A HYBRID ZONE ON MOUNT ETNA, SICILY

Evolution ◽  
2005 ◽  
Vol 59 (12) ◽  
pp. 2533 ◽  
Author(s):  
Juliet K. James ◽  
Richard J. Abbott
Keyword(s):  
Hybrid Zone ◽  
Mount Etna ◽  
Hybrid Speciation ◽  
British Isles ◽  
Homoploid Hybrid

scholarly journals The genomic and ecological context of hybridization affect the probability that symmetrical incompatibilities drive hybrid speciation

2017 ◽  
Author(s):  
Aaron A. Comeault
Keyword(s):  
Hybrid Zone ◽  
Genetic Architecture ◽  
Theoretical Work ◽  
Hybrid Speciation ◽  
Parent Species ◽  
Ecological Context ◽  
Linear Arrangement ◽  
Hybrid Species ◽  
Homoploid Hybrid ◽  
Linkage Relationships

AbstractDespite examples of homoploid hybrid species, theoretical work describing when, where, and how we expect homoploid hybrid speciation to occur remains relatively rare. Here I explore the probability of homoploid hybrid speciation due to “symmetrical incompatibilities” under different selective and genetic scenarios. Through simulation, I test how genetic architecture and selection acting on traits that do not themselves generate incompatibilities interact to affect the probability that hybrids evolve symmetrical incompatibilities with their parent species. Unsurprisingly, selection against admixture at ‘adaptive’ loci that are linked to loci that generate incompatibilities tends to reduce the probability of evolving symmetrical incompatibilities. By contrast, selection that favors admixed genotypes at adaptive loci can promote the evolution of symmetrical incompatibilities. The magnitude of these outcomes is affected by the strength of selection, aspects of genetic architecture such as linkage relationships and the linear arrangement of loci along a chromosome, and the amount of hybridization following the formation of a hybrid zone. These results highlight how understanding the nature of selection, aspects of the genetics of traits affecting fitness, and the strength of reproductive isolation between hybridizing taxa can all be used to inform when we expect to observe homoploid hybrid speciation due to symmetrical incompatibilities.

scholarly journals The Timing and Direction of Introgression Under the Multispecies Network Coalescent

Genetics ◽  
2019 ◽  
Vol 211 (3) ◽  
pp. 1059-1073 ◽  
Author(s):  
Mark S. Hibbins ◽  
Matthew W. Hahn
Keyword(s):  
Statistical Methods ◽  
Biological Process ◽  
Genomic Data ◽  
Hybrid Speciation ◽  
Saccharomyces Paradoxus ◽  
Genomic Signatures ◽  
Wild Yeast ◽  
Other Information ◽  
Homoploid Hybrid ◽  
New Statistics

Introgression is a pervasive biological process, and many statistical methods have been developed to infer its presence from genomic data. However, many of the consequences and genomic signatures of introgression remain unexplored from a methodological standpoint. Here, we develop a model for the timing and direction of introgression based on the multispecies network coalescent, and from it suggest new approaches for testing introgression hypotheses. We suggest two new statistics, D1 and D2, which can be used in conjunction with other information to test hypotheses relating to the timing and direction of introgression, respectively. D1 may find use in evaluating cases of homoploid hybrid speciation (HHS), while D2 provides a four-taxon test for polarizing introgression. Although analytical expectations for our statistics require a number of assumptions to be met, we show how simulations can be used to test hypotheses about introgression when these assumptions are violated. We apply the D1 statistic to genomic data from the wild yeast Saccharomyces paradoxus—a proposed example of HHS—demonstrating its use as a test of this model. These methods provide new and powerful ways to address questions relating to the timing and direction of introgression.

scholarly journals Transient hybridization, not homoploid hybrid speciation, between ancient and deeply divergent conifers

2016 ◽  
Vol 103 (2) ◽  
pp. 246-259 ◽  
Author(s):  
J. R. P. Worth ◽  
M. J. Larcombe ◽  
S. Sakaguchi ◽  
J. R. Marthick ◽  
D. M. J. S. Bowman ◽  
...  
Keyword(s):  
Hybrid Speciation ◽  
Homoploid Hybrid

Homoploid hybrid speciation in action

Taxon ◽  
2010 ◽  
Vol 59 (5) ◽  
pp. 1375-1386 ◽  
Author(s):  
Richard J. Abbott ◽  
Matthew J. Hegarty ◽  
Simon J. Hiscock ◽  
Adrian C. Brennan
Keyword(s):  
Hybrid Speciation ◽  
Homoploid Hybrid

scholarly journals Behavioural isolation may facilitate homoploid hybrid speciation in cichlid fish

2013 ◽  
Vol 27 (2) ◽  
pp. 275-289 ◽  
Author(s):  
O. M. Selz ◽  
R. Thommen ◽  
M. E. Maan ◽  
O. Seehausen
Keyword(s):  
Cichlid Fish ◽  
Hybrid Speciation ◽  
Homoploid Hybrid

scholarly journals Homoploid hybrid speciation and genome evolution via chromosome sorting

2015 ◽  
Vol 282 (1807) ◽  
pp. 20150157 ◽  
Author(s):  
Vladimir A. Lukhtanov ◽  
Nazar A. Shapoval ◽  
Boris A. Anokhin ◽  
Alsu F. Saifitdinova ◽  
Valentina G. Kuznetsova
Keyword(s):  
Reproductive Isolation ◽  
Direct Consequence ◽  
Convincing Evidence ◽  
Interspecific Crosses ◽  
Parental Origin ◽  
Hybrid Speciation ◽  
Species Formation ◽  
Homoploid Hybrid ◽  
Creative Role

Genomes of numerous diploid plant and animal species possess traces of interspecific crosses, and many researches consider them as support for homoploid hybrid speciation (HHS), a process by which a new reproductively isolated species arises through hybridization and combination of parts of the parental genomes, but without an increase in ploidy. However, convincing evidence for a creative role of hybridization in the origin of reproductive isolation between hybrid and parental forms is extremely limited. Here, through studying Agrodiaetus butterflies, we provide proof of a previously unknown mode of HHS based on the formation of post-zygotic reproductive isolation via hybridization of chromosomally divergent parental species and subsequent fixation of a novel combination of chromosome fusions/fissions in hybrid descendants. We show that meiotic segregation, operating in the hybrid lineage, resulted in the formation of a new diploid genome, drastically rearranged in terms of chromosome number. We also demonstrate that during the heterozygous stage of the hybrid species formation, recombination was limited between rearranged chromosomes of different parental origin, representing evidence that the reproductive isolation was a direct consequence of hybridization.

scholarly journals Young inversion with multiple linked QTLs under selection in a hybrid zone

2017 ◽  
Vol 1 (5) ◽  
Author(s):  
Cheng-Ruei Lee ◽  
Baosheng Wang ◽  
Julius P. Mojica ◽  
Terezie Mandáková ◽  
Kasavajhala V. S. K. Prasad ◽  
...  
Keyword(s):  
Hybrid Zone ◽  
High Frequency ◽  
Direct Evidence ◽  
Hybrid Speciation ◽  
Incipient Speciation ◽  
Inversion Region ◽  
Chromosomal Inversions ◽  
Multiple Loci ◽  
Last Glaciation ◽  
Boechera Stricta

Abstract Fixed chromosomal inversions can reduce gene flow and promote speciation in two ways: by suppressing recombination and by carrying locally favoured alleles at multiple loci. However, it is unknown whether favoured mutations slowly accumulate on older inversions or if young inversions spread because they capture pre-existing adaptive quantitative trait loci (QTLs). By genetic mapping, chromosome painting and genome sequencing, we have identified a major inversion controlling ecologically important traits in Boechera stricta. The inversion arose since the last glaciation and subsequently reached local high frequency in a hybrid speciation zone. Furthermore, the inversion shows signs of positive directional selection. To test whether the inversion could have captured existing, linked QTLs, we crossed standard, collinear haplotypes from the hybrid zone and found multiple linked phenology QTLs within the inversion region. These findings provide the first direct evidence that linked, locally adapted QTLs may be captured by young inversions during incipient speciation.

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