scholarly journals Origin and cross-century dynamics of an avian hybrid zone

2014 ◽  
Author(s):  
Andrea Morales-Rozo ◽  
Elkin A. Tenorio ◽  
Matthew D. Carling ◽  
Carlos Daniel Cadena
Keyword(s):  
Hybrid Zone ◽  
Secondary Contact ◽  
Population Divergence ◽  
Climatic Data ◽  
Hybrid Zones ◽  
Spatial Analyses ◽  
Demographic Expansion ◽  
Phenotypic Characters ◽  
Genetic Signatures ◽  
Phenotypic Cline

AbstractBackgroundCharacterizations of the dynamics of hybrid zones in space and time can give insights about traits and processes important in population divergence and speciation. We characterized a hybrid zone between tanagers in the genus Ramphocelus (Aves, Thraupidae) located in southwestern Colombia. We tested whether this hybrid zone originated as a result of secondary contact or of primary differentiation, and described its dynamics across time using spatial analyses of molecular, morphological, and coloration data in combination with paleodistribution modeling.ResultsModels of potential historical distributions based on climatic data and genetic signatures of demographic expansion suggested that the hybrid zone likely originated following secondary contact between populations that expanded their ranges out of isolated areas in the Quaternary. Concordant patterns of variation in phenotypic characters across the hybrid zone and its narrow extent are suggestive of a tension zone, maintained by a balance between dispersal and selection against hybrids. Estimates of phenotypic cline parameters obtained using specimens collected over nearly a century revealed that, in recent decades, the zone appears to have moved to the east and to higher elevations, and has apparently become narrower. Genetic variation was not clearly structured along the hybrid zone, but comparisons between historical and contemporary specimens suggested that temporal changes in its genetic makeup may also have occurred.ConclusionsOur data suggest that the hybrid zone likey resulted from secondary contact between populations. The observed changes in the hybrid zone may be a result of sexual selection, asymmetric gene flow, or environmental change.

How often do they do it? An in-depth analysis of the hybrid zone of two grass snake species (Natrix astreptophora and Natrix helvetica)

2020 ◽  
Vol 131 (4) ◽  
pp. 756-773
Author(s):  
Marika Asztalos ◽  
Nadine Schultze ◽  
Flora Ihlow ◽  
Philippe Geniez ◽  
Matthieu Berroneau ◽  
...  
Keyword(s):  
Contact Zone ◽  
Hybrid Zone ◽  
Climatic Conditions ◽  
Secondary Contact ◽  
Distribution Models ◽  
Long Distance ◽  
Depth Analysis ◽  
Grass Snake ◽  
Genetic Signatures ◽  
Cline Width

Abstract We examined the contact zone of two parapatric species of grass snake (Natrix astreptophora and Natrix helvetica) in southern France. To this end, we used comprehensive sampling, analysed mtDNA sequences and microsatellite loci, and built Species Distribution Models for current and past climatic conditions. The contact zone had established by the mid-Holocene during range expansions from glacial refuges in the Iberian Peninsula (N. astreptophora) and southern or western France (N. helvetica). The contact zone represents a narrow bimodal hybrid zone, with steep genetic transition from one taxon to the other and rare hybridization, supporting species status for N. astreptophora and N. helvetica. Our results suggest that the steepness of the clines is a more robust tool for species delimitation than cline width. In addition, we discovered in western France, beyond the hybrid zone, a remote population of N. helvetica with genetic signatures of hybridization with N. astreptophora, most likely the result of human-mediated long-distance dispersal. For N. helvetica, we identified a southern and a northern population cluster, connected by broad-scale gene flow in a unimodal hybrid zone running across France. This pattern either reflects genetic divergence caused by allopatry in two microrefuges and subsequent secondary contact or introgression of foreign alleles into the southern cluster.

scholarly journals Asymmetric Reproductive Barriers and Gene Flow Promote the Rise of a Stable Hybrid Zone in the Mediterranean High Mountain

2021 ◽  
Vol 12 ◽  
Author(s):  
Mohamed Abdelaziz ◽  
A. Jesús Muñoz-Pajares ◽  
Modesto Berbel ◽  
Ana García-Muñoz ◽  
José M. Gómez ◽  
...  
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sierra Nevada ◽  
Hybrid Zone ◽  
High Elevation ◽  
Secondary Contact ◽  
High Mountain ◽  
Hybrid Zones ◽  
Reproductive Barriers ◽  
Sierra Nevada Mountains

Hybrid zones have the potential to shed light on evolutionary processes driving adaptation and speciation. Secondary contact hybrid zones are particularly powerful natural systems for studying the interaction between divergent genomes to understand the mode and rate at which reproductive isolation accumulates during speciation. We have studied a total of 720 plants belonging to five populations from two Erysimum (Brassicaceae) species presenting a contact zone in the Sierra Nevada mountains (SE Spain). The plants were phenotyped in 2007 and 2017, and most of them were genotyped the first year using 10 microsatellite markers. Plants coming from natural populations were grown in a common garden to evaluate the reproductive barriers between both species by means of controlled crosses. All the plants used for the field and greenhouse study were characterized by measuring traits related to plant size and flower size. We estimated the genetic molecular variances, the genetic differentiation, and the genetic structure by means of the F-statistic and Bayesian inference. We also estimated the amount of recent gene flow between populations. We found a narrow unimodal hybrid zone where the hybrid genotypes appear to have been maintained by significant levels of a unidirectional gene flow coming from parental populations and from weak reproductive isolation between them. Hybrid plants exhibited intermediate or vigorous phenotypes depending on the analyzed trait. The phenotypic differences between the hybrid and the parental plants were highly coherent between the field and controlled cross experiments and through time. The highly coherent results obtained by combining field, experimental, and genetic data demonstrate the existence of a stable and narrow unimodal hybrid zone between Erysimum mediohispanicum and Erysimum nevadense at the high elevation of the Sierra Nevada mountains.

Divergence and speciation as viewed from an insect hybrid zone

1990 ◽  
Vol 68 (8) ◽  
pp. 1701-1715 ◽  
Author(s):  
Godfrey M. Hewitt
Keyword(s):  
Hybrid Zone ◽  
Genetic Material ◽  
Mate Recognition ◽  
Life Forms ◽  
Point Of View ◽  
Divergent Evolution ◽  
Secondary Contact ◽  
Hybrid Zones ◽  
Recognition Systems ◽  
Contraction And Expansion

Hybridism is examined both from Darwin's point of view and in light of current views on the species concept. It seems that many of the relevant concepts of population genetics and speciation are inherent in primitive molecular evolution and may be useful in explaining divergent evolution from the earliest life forms. When divergent genomes meet they may hybridize and, in many cases, form a hybrid zone. Work on insect hybrid zones is used to exemplify the factors and processes involved. Many such zones are the result of postglacial secondary contact and involve some form of hybrid unfitness. They usually comprise multigenic differences and each gene may have different properties. Two grasshoppers, Podisma pedestris and Chorthippus parallelus, are used as case studies. In the case of P. pedestris, as a result of vegetation analysis, it is possible to be fairly sure that the zone is not environmentally determined but rather the result of heterozygous disadvantage at many loci. In the other species, in which two divergent mate recognition systems meet, there is no evidence of their reinforcement toward speciation, despite the F1 hybrids showing severe testis dysfunction and providing another example of Haldane's rule. A scenario for the postglacial contact and hybridization is proferred in an attempt to explain differences between disjunct sections of the zone. It is argued that gene flow occurs over only very small distances in hybrid zones and that the zones themselves will not move far because they fall in low density traps. Compound hybrid zones may be formed by cycles of range contraction and expansion and the substructure of a species will be determined by its life style. Hybrid zones provide a demonstration that divergence occurs in various characters at different rates and divergence brings with it hybrid disadvantage and frequency dependence. Speciation is seen as some way down this path, but occasional transfers of genetic material may still occur.

scholarly journals The effects of frequency-dependent sexual selection, mating-trait architecture and matching rule on hybrid zone dynamics in crows

2020 ◽  
Author(s):  
Dirk Metzler ◽  
Ulrich Knief ◽  
Joshua V. Peñalba ◽  
Jochen B. W. Wolf
Keyword(s):  
Sexual Selection ◽  
Assortative Mating ◽  
Hybrid Zone ◽  
Secondary Contact ◽  
Hybrid Zones ◽  
Moderate Degree ◽  
Matching Rule ◽  
Trait Loci ◽  
Spatio Temporal ◽  
Hooded Crows

AbstractHybrid zones provide a window into the evolutionary processes governing species divergence. While the role of postzygotic isolation has been extensively characterized in the context of hybrid zones, the contribution of prezygotic isolation is less well explored. In particular, the effect of assortative mate choice, the underlying preference function, the architecture of the mating trait and the strength of sexual selection are worthy of investigation. Here, we explore this question by means of a mathematical model parameterized with empirical data from the hybrid zone between all-black carrion and grey-coated hooded crows. The best-fit model resulted in narrow clines for two mating-trait loci coding for colour phenotype maintained by a moderate degree of assortative mating. Epistasis between the two loci induced hybrid-zone movement in favor of alleles conveying dark plumage followed by a shift in the opposite direction favouring grey-coated phenotypes ∼1,200 generations after secondary contact. Unlinked neutral loci diffused near-unimpeded across the zone. This study demonstrates that sexual selection created by assortative mating can explain steep transitions in mating-trait loci without generalizing to genome-wide reproductive isolation. It further emphasizes the importance of mating-trait architecture for spatio–temporal hybrid-zone dynamics.

scholarly journals Population genomics of parallel hybrid zones in the mimetic butterflies, H. melpomene and H. erato

2013 ◽  
Author(s):  
Nicola Nadeau ◽  
Mayte Ruiz ◽  
Patricio Salazar ◽  
Brian Counterman ◽  
Jose Alejandro Medina ◽  
...  
Keyword(s):  
Population Genomics ◽  
De Novo ◽  
Reference Sequence ◽  
Colour Pattern ◽  
Adaptive Divergence ◽  
Population Divergence ◽  
Hybrid Zones ◽  
Data Alignment ◽  
Parallel Hybrid ◽  
Genomic Regions

Hybrid zones can be valuable tools for studying evolution and identifying genomic regions responsible for adaptive divergence and underlying phenotypic variation. Hybrid zones between subspecies of Heliconius butterflies can be very narrow and are maintained by strong selection acting on colour pattern. The co-mimetic species H. erato and H. melpomene have parallel hybrid zones where both species undergo a change from one colour pattern form to another. We use restriction associated DNA sequencing to obtain several thousand genome wide sequence markers and use these to analyse patterns of population divergence across two pairs of parallel hybrid zones in Peru and Ecuador. We compare two approaches for analysis of this type of data; alignment to a reference genome and de novo assembly, and find that alignment gives the best results for species both closely (H. melpomene) and distantly (H. erato, ~15% divergent) related to the reference sequence. Our results confirm that the colour pattern controlling loci account for the majority of divergent regions across the genome, but we also detect other divergent regions apparently unlinked to colour pattern differences. We also use association mapping to identify previously unmapped colour pattern loci, in particular the Ro locus. Finally, we identify within our sample a new cryptic population of H. timareta in Ecuador, which occurs at relatively low altitude and is mimetic with H. melpomene malleti.

scholarly journals Intraspecific Molecular Variation of Allium ursinum (Amaryllidaceae) Across the Border of Two Subspecies Distribution Ranges

2015 ◽  
Vol 57 (1) ◽  
pp. 31-43
Author(s):  
Kaja Rola ◽  
Anna Lenart-Boroń ◽  
Piotr Boroń ◽  
Piotr Osyczka
Keyword(s):  
Genetic Variability ◽  
Hybrid Zone ◽  
Mantel Test ◽  
Genetic Group ◽  
Secondary Contact ◽  
Putative Hybrid ◽  
Morphological Pattern ◽  
The Third ◽  
Allium Ursinum ◽  
Distribution Ranges

Abstract The study investigates the genetic differentiation among two subspecies of Allium ursinum L., namely A. ursinum subsp. ursinum and subsp. ucrainicum as well as their putative hybrid that is represented by individuals with intermediate morphology. Inter-Simple Sequence Repeats (ISSR) were applied to determine the status of intermediate morphotypes in terms of their genetic pattern and to assess the level of genetic variability within and between various populations of A. ursinum. The study comprises 144 specimens from nine populations along the east-west transect in Poland, which includes localities of both subspecies and their putative hybrid. Among the examined populations, 48 bands were amplified, of which 45 were found to be polymorphic. The principal coordinate analysis (PCoA), the neighbour-net analysis and Mantel test showed a strong correlation between genetic variability and geographic distance. Analysis of molecular variance (AMOVA) revealed that a greater proportion of total genetic variation resided within populations rather than among them. The Structure Bayesian clustering analysis revealed the presence of three distinct genetic groups within studied populations, where ‘eastern’ genotypes correspond to A. ursinum subsp. ucrainicum, and ‘western’ to subsp. ursinum; whereas the third genetic group has the largest share in the individuals occurring at the border of the distribution ranges of both subspecies. The emergence of the third genetic group is probably an effect of hybridization events occurring within the secondary contact zone. Typical morphologically intermediate populations occur only in a relatively narrow geographical zone, but the hybrid zone revealed by molecular markers is actually much wider than it is suggested by the morphological pattern of individuals. The current distribution pattern of both subspecies of A. ursinum and their hybrid zone is related to the two main directions of postglacial migration of Fagus sylvatica to the area of Poland. The hybrid zone arose as an effect of the secondary contact of two divergent lineages of A. ursinum.

Extensive hybridization between two Andean warbler species with shallow divergence in mtDNA

The Auk ◽  
2021 ◽  
Vol 138 (1) ◽  
Author(s):  
Laura N Céspedes-Arias ◽  
Andrés M Cuervo ◽  
Elisa Bonaccorso ◽  
Marialejandra Castro-Farias ◽  
Alejandro Mendoza-Santacruz ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Contact Zone ◽  
Hybrid Zone ◽  
Secondary Contact ◽  
Tropical Andes ◽  
Phenotypic Data ◽  
Geographic Ranges ◽  
Intermediate Phenotypes ◽  
Ecological Barriers

Abstract Studying processes acting on differentiated populations upon secondary contact, such as hybridization, is important to comprehensively understand how species are formed and maintained over time. However, avian speciation studies in the tropical Andes have largely focused on the role of topographic and ecological barriers promoting divergence in allopatry, seldom examining hybridization and introgression. We describe a hybrid zone involving 2 closely related Andean warblers (Parulidae), the Golden-fronted Redstart (Myioborus ornatus), and the Spectacled Redstart (Myioborus melanocephalus). Geographic ranges of these species abut near the Colombia-Ecuador border and many specimens from the region exhibit intermediate phenotypes, but a formal description of phenotypic variation in the contact zone was heretofore lacking. We collected specimens across a transect encompassing the area where ranges abut and areas where only “pure” parental phenotypes of M. ornatus chrysops and M. melanocephalus ruficoronatus occur. We described variation in plumage traits including patterns of head and ventral coloration and tail markings based on 321 specimens. To describe genetic variation in the contact zone and over a broader phylogeographic context, we used sequences of the mitochondrial ND2 gene for 219 individuals across the transect and the entire range of both species, including all subspecies, from Venezuela to Bolivia. We documented a hybrid zone ~200 km wide based on head coloration, where intermediate plumage phenotypes are most common and “pure” forms do not overlap geographically, consistent with extensive hybridization. Across the range of the M. ornatus–M. melanocephalus complex, mitochondrial genetic structure was shallow, with genetic breaks only coinciding clearly with one topographic feature. Such a low genetic structure is striking given the high diversity in plumage phenotypes and the current taxonomy of the group. Our phenotypic data suggest that barriers to hybridization are not strong, and allow us to postulate hypotheses to be tested using forthcoming genomic data.

The distribution and biogeography of slow worms (Anguis, Squamata) across the Western Palearctic, with an emphasis on secondary contact zones

2021 ◽  
pp. 1-12
Author(s):  
Daniel Jablonski ◽  
Neftalí Sillero ◽  
Oleksandra Oskyrko ◽  
Adriana Bellati ◽  
Andris Čeirāns ◽  
...  
Keyword(s):  
Natural History ◽  
Genetic Data ◽  
Secondary Contact ◽  
Hybrid Zones ◽  
Grey Zone ◽  
Contact Zones ◽  
Distribution Maps ◽  
Western Palearctic ◽  
Southern Balkans

Abstract The slow-worm lizards (Anguis) comprise five species occurring throughout most of the Western Palearctic. Although these species are relatively uniform morphologically – with the exception of A. cephallonica, which exhibits a quite unique morphology – they are genetically deeply divergent. Here, we provide detailed distribution maps for each species and discuss their biogeography and conservation based on updated genetic data and a robust distribution database. We pay particular attention to the so called ‘grey zone’, which typically represents secondary contact zones and in some cases confirmed or presumed hybrid zones. Four of the five species live in parapatry, while only two species, A. cephallonica and A. graeca from the southern Balkans occur in partial sympatry. Further research should focus on the eco-evolutionary interactions between species in contact, including their hybridization rates, to reveal deeper details of the slow-worm evolutionary and natural history.

A revision of the shield-back katydid genus Neduba (Orthoptera: Tettigoniidae: Tettigoniinae: Nedubini)

Zootaxa ◽  
2021 ◽  
Vol 4910 (1) ◽  
pp. 1-92
Author(s):  
JEFFREY A. COLE ◽  
DAVID B. WEISSMAN ◽  
DAVID C. LIGHTFOOT ◽  
NORIHIRO UESHIMA ◽  
ELŻBIETA WARCHAŁOWSKA-ŚLIWA ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Junior Synonym ◽  
Species Boundaries ◽  
Secondary Contact ◽  
Conservation Priorities ◽  
Hybrid Zones ◽  
Environmental Disturbance ◽  
Western North America ◽  
Molecular Phylogenetic

The Nearctic shield-back katydid genus Neduba is revised. Species boundaries were demarcated by molecular phylogenetic analysis, morphology, quantitative analysis of calling songs, and karyotypes. Nine previously described species are redescribed: N. carinata, N. castanea, N. convexa, N. diabolica, N. extincta, N. macneilli, N. propsti, N. sierranus, and N. steindachneri, and twelve new species are described: N. ambagiosa sp. n., N. arborea sp. n., N. cascadia sp. n., N. duplocantans sp. n., N. inversa sp. n., N. longiplutea sp. n., N. lucubrata sp. n., N. oblongata sp. n., N. prorocantans sp. n., N. radicata sp. n., N. radocantans sp. n., and N. sequoia sp. n. We chose a lectotype for N. steindachneri and transferred N. picturata from a junior synonym of N. diabolica to a junior synonym of N. steindachneri. Diversification in this relict group reflects cycles of allopatric isolation and secondary contact amidst the tumultuous, evolving geography of western North America. The taxonomy and phylogenies presented in this revision lay the groundwork for studies of speciation, biogeography, hybrid zones, and behavioral evolution. Given that one Neduba species is already extinct from human environmental disturbance, we suggest conservation priorities for the genus. 

scholarly journals Influence of Niche Overlap and Territoriality on Hybridization Between Hermit Warblers and Townsend's Warblers

The Auk ◽  
2000 ◽  
Vol 117 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Scott F. Pearson ◽  
David A. Manuwal
Keyword(s):  
Habitat Use ◽  
Hybrid Zone ◽  
Parental Species ◽  
Niche Overlap ◽  
Habitat Characteristics ◽  
Hybrid Zones ◽  
Parental Fitness ◽  
Habitat Transition ◽  
Habitat Variables ◽  
Washington Cascades

Abstract Hybrid zones between Townsend's Warblers (Dendroica townsendi) and Hermit Warblers (D. occidentalis) in the Pacific Northwest are narrow relative to estimated dispersal distances and appear to be moving, with Townsend's replacing Hermits. We examined whether the habitat-transition and parental-fitness asymmetry models can explain why these zones are narrow and moving by comparing habitat variables associated with warbler territories in the Washington Cascades hybrid zone. Habitat variables did not differ among phenotypes, suggesting that the habitat-transition model cannot explain the narrow and dynamic nature of this hybrid zone. Habitat characteristics of Hermit Warbler territories did not differ inside versus outside the hybrid zone, also suggesting that this zone is not associated with a region of habitat transition. The lack of difference in habitat use could be the result of comparing variables that are not important to pairing success. However, warblers tended to select territories on west-southwest aspects. South aspects in the southern Washington Cascades are dominated by Douglas fir (Pseudotsuga menziesii) and true fir, which is a habitat selected by female warblers when choosing among territories and males. The parental-fitness asymmetry model does not necessarily make predictions about habitat use within the hybrid zone but predicts the superiority of one parental species over the other. However, if significant overlap occurs in habitat use or niche (as in these warblers), then competition between parental species is likely to occur. To determine whether these species compete, we mapped 12 warbler territories and monitored an additional 94 territories throughout the breeding season and found that all males with neighbors compete for and hold exclusive territories. Thus, the pattern of habitat use and territoriality is consistent with the parental-fitness asymmetry model.

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