scholarly journals 3D Geometric Morphometrics Reveals Convergent Character Displacement in the Central European Contact Zone between Two Species of Hedgehogs (Genus Erinaceus)

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1803
Author(s):  
Barbora Černá Bolfíková ◽  
Allowen Evin ◽  
Markéta Rozkošná Knitlová ◽  
Miroslava Loudová ◽  
Anna Sztencel-Jabłonka ◽  
...  
Keyword(s):  
Geometric Morphometrics ◽  
Contact Zone ◽  
Character Displacement ◽  
Anthropogenic Factors ◽  
Secondary Contact ◽  
Adaptive Landscape ◽  
Clinal Variation ◽  
Mesopredator Release ◽  
Subsequent Formation ◽  
Evolutionary Forces

Hedgehogs, as medium-sized plantigrade insectivores with low basal metabolic rates and related defensive anti-predator strategies, are quite sensitive to temperature and ecosystem productivity. Their ranges therefore changed dramatically due to Pleistocene climate oscillations, resulting in allopatric speciation and the subsequent formation of secondary contact zones. Such interactions between closely related species are known to generate strong evolutionary forces responsible for niche differentiation. In this connection, here, we detail the results of research on the phenotypic evolution in the two species of hedgehog present in central Europe, as based on genetics and geometric morphometrics in samples along a longitudinal transect that includes the contact zone between the species. While in allopatry, Erinaceus europaeus is found to have a larger skull than E. roumanicus and distinct cranial and mandibular shapes; the members of the two species in sympatry are smaller and more similar to each other, with a convergent shape of the mandible. The relevant data fail to reveal any major role for either hybridisation or clinal variation. We, therefore, hypothesise that competitive pressure exerted on the studied species does not generate divergent selection sufficient for divergent character displacement to evolve, instead giving rise to convergent selection in the face of resource limitation in the direction of smaller skull size. Considering the multi-factorial constraints present in the relevant adaptive landscape, reduction in size could also be facilitated by predator pressure in ecosystems characterised by mesopredator release and other anthropogenic factors. As the function of the animals’ lower jaw is mainly connected with feeding (in contrast to the cranium whose functions are obviously more complex), we interpret the similarity in shape as reflecting local adaptations to overlapping dietary resources in the two species and hence as convergent character displacement.

scholarly journals Morphological variation in two genetically distinct groups of the golden-striped salamander, Chioglossa lusitanica (Amphibia: Urodela)

2005 ◽  
Vol 74 (3-4) ◽  
pp. 213-222 ◽  
Author(s):  
J. Alexandrino ◽  
N. Ferrand ◽  
J.W. Arntzen ◽  
João Alexandrino
Keyword(s):  
Contact Zone ◽  
Environmental Gradient ◽  
Early Pleistocene ◽  
Colour Pattern ◽  
Secondary Contact ◽  
Clinal Variation ◽  
The North ◽  
Secondary Contact Zone ◽  
Pattern Variability ◽  
Chioglossa Lusitanica

Morphometric and colour pattern variation in the endemic Iberian salamander Chioglossa lusitanica is concordant with the genetic differentiation of two groups of populations separated by the Mondego river in Portugal. Salamanders from the south have shorter digits than those from the north. Clinal variation with a south to north increase in limb, toe and finger length was found superimposed on this dichotomy, resulting in stepped clines for characters describing appendage size. Genetic variability was paralleled by colour pattern variability in the contact zone and in northern populations. To explain the observed parallels we invoke the neutral processes of vicariant isolation, admixture in a secondary contact zone, genetic drift in addition to selection acting along an environmental gradient. Morphological constraints imposed by a highly specialized ecological niche may explain why the genetic subdivision of C. lusitanica since the early Pleistocene has remained fairly cryptic.

scholarly journals Secondary contact and local adaptation contribute to genome-wide patterns of clinal variation in Drosophila melanogaster

2014 ◽  
Author(s):  
Alan O. Bergland ◽  
Ray Tobler ◽  
Josefa Gonzalez ◽  
Paul Schmidt ◽  
Dmitri Petrov
Keyword(s):  
Drosophila Melanogaster ◽  
North America ◽  
Local Adaptation ◽  
Latitudinal Gradients ◽  
Secondary Contact ◽  
Clinal Variation ◽  
Evolutionary Forces ◽  
Genome Wide ◽  
Spatially Varying ◽  
Spatially Varying Selection

Populations arrayed along broad latitudinal gradients often show patterns of clinal variation in phenotype and genotype. Such population differentiation can be generated and maintained by historical demographic events and local adaptation. These evolutionary forces are not mutually exclusive and, moreover, can in some cases produce nearly identical patterns of genetic differentiation among populations. Here, we investigate the evolutionary forces that generated and maintain clinal variation genome-wide among populations ofDrosophila melanogastersampled in North America and Australia. We contrast patterns of clinal variation in these continents with patterns of differentiation among ancestral European and African populations. Using established and novel methods we derive here, we show that recently derived North America and Australia populations were likely founded by both European and African lineages and that this admixture event contributed to genome-wide patterns of parallel clinal variation. The pervasive effects of admixture meant that only a handful of loci could be attributed to the operation of spatially varying selection using an FST outlier approach. Our results provide novel insight into the well-studied system of clinal differentiation inD. melanogasterand provide a context for future studies seeking to identify loci contributing to local adaptation in a wide variety of organisms, including other invasive species as well as some temperate endemics.

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.

Cryptic Diversity and Sexual Selection

2020 ◽  
pp. 447-471
Author(s):  
Matthias Galipaud ◽  
Loïc Bollache ◽  
Clément Lagrue
Keyword(s):  
Sexual Selection ◽  
Morphological Traits ◽  
Character Displacement ◽  
Secondary Contact ◽  
Cryptic Diversity ◽  
Reproductive Character Displacement ◽  
Behavioral Traits ◽  
Genetic Techniques ◽  
Existing Data

Recent advances in molecular and genetic techniques have revealed tremendous hidden genetic diversity in plants and animals. Crustaceans are no exception and, in fact, present one of the highest levels of cryptic diversity among the metazoans. Beyond the importance of such discovery and its multiple implications for taxonomy and ecology, it is now timely to investigate the potential causes of cryptic diversity. This chapter reviews the theoretical and experimental literature, seeking evidences for a relationship between sexual selection and cryptic diversity in crustaceans. It proposes three scenarios for the role of sexual selection on the origin and maintenance of pre-mating isolation and genetic divergence among crustacean populations, and suggests ways to discriminate among them experimentally or using existing data. Assuming that taxonomic identification is largely based on differences in sexually selected morphological traits, it also reviews evidence for a cryptic action of sexual selection on crustacean phenotypes. Specifically, if sexual selection acts primarily on chemical, visual, or behavioral traits, it is likely that allopatric crustacean populations remain morphologically similar even when they are reproductively isolated. This review shows that the strength of sexual selection likely differs among allopatric populations but does not seem to consistently induce pre-mating isolation (e.g. as in copepods and amphipods). Research is now needed to try to identify general patterns and determine the role of sexual selection on pre-mating isolation after secondary contact between populations, through reinforcement and reproductive character displacement.

Phenotypic clines across an unstudied hybrid zone in Woodhouse’s Scrub-Jay (Aphelocoma woodhouseii)

The Auk ◽  
2019 ◽  
Vol 136 (2) ◽  
Author(s):  
Devon A DeRaad ◽  
James M Maley ◽  
Whitney L E Tsai ◽  
John E McCormack
Keyword(s):  
Body Size ◽  
Contact Zone ◽  
Mexico City ◽  
Rocky Mountains ◽  
Secondary Contact ◽  
Genetic Isolation ◽  
Southern Mexico ◽  
Phenotypic Differences ◽  
Northern Mexico ◽  
Group A

Abstract Woodhouse’s Scrub-Jay (Aphelocoma woodhouseii) comprises 7 subspecies, ranging from the Rocky Mountains to southern Mexico. We quantified the phenotype of specimens throughout Mexico and found support for significant phenotypic differences between “Sumichrast’s group” in southern Mexico (A. w. sumichrasti and A. w. remota) and the 2 subspecies in northern Mexico, or “Woodhouse’s group” (A. w. grisea and A. w. cyanotis). Despite significant differentiation in body size and mantle color, we found no clear geographic boundary between the groups, suggesting either a geographic cline or hybridization upon secondary contact. We tested for selection against hybridization by fitting models to geographic clines for both body size and back color, and found support for a stable contact zone centered near Mexico City, with selection against intermediate back color. Based on these results, we infer that Sumichrast’s and Woodhouse’s groups diverged during a period of geographic and genetic isolation. The phenotypic introgression between Sumichrast’s and Woodhouse’s groups near Mexico City likely represents a case of recent secondary contact, with selection against hybridization maintaining a geographically stable contact zone.

scholarly journals Phylogeography of the Neotropical epiphytic orchid, Brassavola nodosa: evidence for a secondary contact zone in northwestern Costa Rica

Heredity ◽  
2019 ◽  
Vol 123 (5) ◽  
pp. 662-674
Author(s):  
Dorset W. Trapnell ◽  
J. L. Hamrick ◽  
Patrick A. Smallwood ◽  
Tyler R. Kartzinel ◽  
Caitlin D. Ishibashi ◽  
...  
Keyword(s):  
Costa Rica ◽  
Contact Zone ◽  
Secondary Contact ◽  
Epiphytic Orchid ◽  
Secondary Contact Zone

Asymmetric acoustic signal recognition led to asymmetric gene flow between two parapatric frogs

2020 ◽  
Author(s):  
Yu-Wei Hsiao ◽  
Hui-Yun Tseng ◽  
Hung Ngoc Nguyen ◽  
Si-Min Lin
Keyword(s):  
Gene Flow ◽  
Contact Region ◽  
Character Displacement ◽  
Secondary Contact ◽  
Genetic Introgression ◽  
Genetic Integrity ◽  
Signal Recognition ◽  
Reproductive Character Displacement ◽  
Reproductive Character ◽  
Behavioural Experiments

Abstract Correct discrimination between courtship signals could help to maintain genetic integrity between closely related species. However, asymmetric usage of signals might cause asymmetric gene flow across the contact zone. Buergeria choui and B. otai are sibling-species with a parapatric distribution pattern in Taiwan, having two narrow contact zones on the east and west sides of the island. Combining behavioural experiments with genome-wide RAD-seq analyses, we test whether the ability of signal recognition influences genetic introgression across their species boundary. The playback experiments show that all B. choui populations respond strongest to their own ‘cricket’ trills, while the western population of B. otai have evolved a strong level of reproductive character displacement by showing the inclusive usage of the unique ‘chicken’ signals. In contrast, the eastern B. otai population uses both ‘chicken’ and ‘cricket’ trills, and has a stronger preference for the latter. The weak reproductive character displacement in the eastern population has led to asymmetry genetic introgression from B. choui toward B. otai. Our results support the prediction that a more specialized signal-user, compared to its sibling, generalized signal-user, might have a higher probability of maintaining their genetic integrity in the secondary contact region.

scholarly journals Mitochondrial Ecophysiology: Assessing the Evolutionary Forces That Shape Mitochondrial Variation

2019 ◽  
Vol 59 (4) ◽  
pp. 925-937 ◽  
Author(s):  
Jessica L McKenzie ◽  
Dillon J Chung ◽  
Timothy M Healy ◽  
Reid S Brennan ◽  
Heather J Bryant ◽  
...  
Keyword(s):  
Adaptive Evolution ◽  
Mitochondrial Function ◽  
Fundulus Heteroclitus ◽  
Secondary Contact ◽  
Mitochondrial Genomes ◽  
Evolutionary Forces ◽  
Population Genomic ◽  
Genomic Studies

Abstract The mitonuclear species concept hypothesizes that incompatibilities between interacting gene products of the nuclear and mitochondrial genomes are a major factor establishing and maintaining species boundaries. However, most of the data available to test this concept come from studies of genetic variation in mitochondrial DNA, and clines in the mitochondrial genome across contact zones can be produced by a variety of forces. Here, we show that using a combination of population genomic analyses of the nuclear and mitochondrial genomes and studies of mitochondrial function can provide insight into the relative roles of neutral processes, adaptive evolution, and mitonuclear incompatibility in establishing and maintaining mitochondrial clines, using Atlantic killifish (Fundulus heteroclitus) as a case study. There is strong evidence for a role of secondary contact following the last glaciation in shaping a steep mitochondrial cline across a contact zone between northern and southern subspecies of killifish, but there is also evidence for a role of adaptive evolution in driving differentiation between the subspecies in a variety of traits from the level of the whole organism to the level of mitochondrial function. In addition, studies are beginning to address the potential for mitonuclear incompatibilities in admixed populations. However, population genomic studies have failed to detect evidence for a strong and pervasive influence of mitonuclear incompatibilities, and we suggest that polygenic selection may be responsible for the complex patterns observed. This case study demonstrates that multiple forces can act together in shaping mitochondrial clines, and illustrates the challenge of disentangling their relative roles.

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