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180 results for “contact zone”
Data from: Ecological differentiation, lack of hybrids involving diploids, and asymmetric gene flow between polyploids in narrow contact zones of Senecio carniolicus (syn. Jacobaea carniolica, Asteraceae)
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Data from: Interspecific competition promotes habitat and morphological divergence in a secondary contact zone between two hybridizing songbirds
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Data from: Phylogeography of the Neotropical epiphytic orchid, Brassavola nodosa: evidence for a secondary contact zone in northwestern Costa Rica
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Secondary contact zones of closely-related Erebia butterflies overlap with narrow phenotypic and parasitic clines
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Data from: DNA taxonomy in the timber genus Milicia: evidence of unidirectional introgression in the West African contact zone
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Data from: Haldane’s rule revisited: do hybrid females have a shorter lifespan? Survival of hybrids in a recent contact zone between two large gull species
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Parasite turnover zone at secondary contact: a new pattern in host-parasite population genetics
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Data from: Timeframe of speciation inferred from secondary contact zones in the European tree frog radiation (Hyla arborea group)
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Data from: Individual performance in relation to cytonuclear discordance in a northern contact zone between long-toed salamander (Ambystoma macrodactylum) lineages
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From refugia to contact: pine processionary moth hybrid zone in a complex biogeographic setting
<p class="MsoCommentText">Contact zones occur at the crossroad between specific dispersal routes and are facilitated by biogeographic discontinuities. Here we focused on two Lepidoptera sister species that come in contact near the Turkish Straits System (TSS). We aimed to infer their phylogeographic histories in the Eastern Mediterranean and finely analyse their co-occurrence and hybridisation patterns in this biogeographical context.</p> <p class="MsoCommentText">We used molecular mitochondrial and nuclear markers to study 224 individuals from 42 localities. We used discordances between markers and complementary assignment methods to identify and map hybrids and parental individuals.</p> <p class="MsoCommentText">We confirmed the parapatric distribution of <i>Thaumetopoea</i><i> pityocampa </i>(Lepidoptera: Notodontidae) in the west and <i>T. wilkinsoni </i>in the east and identified a narrow contact zone. We identified several glacial refugia of <i>T. wilkinsoni</i> in southern Turkey with a strong east-west differentiation in this species. Unexpectedly, <i>T. pityocampa</i> crossed the TSS and occur in northern Aegean Turkey and some eastern Greek islands. We found robust evidence of introgression between the two species in a restricted zone in north-western Turkey, but we did not identify any F<sub>1</sub> individuals. The identified hybrid zone was mostly bimodal.</p> <p>The distributions and genetic patterns of the studied species were strongly influenced both by the Quaternary climatic oscillations and the complex geological history of the Aegean region. <i>Thaumetopoea pityocampa</i> and <i>T. wilkinsoni</i> survived the last glacial maximum in disjoint refugia and met in western Turkey at the edge of the recolonization routes. Expanding population of<i> T. wilkinsoni</i> constrained <i>T. pityocampa</i> to the western Turkish shore. Additionally, we found evidence of recurrent introgression by <i>T. wilkinsoni</i> males in several <i>T. pityocampa</i> populations. Our results suggest that some prezygotic isolation mechanisms, such as differences in timing of the adult emergences, might be a driver of the isolation between the sister species.</p>
Data from: Genetic data reveal fine-scale ecological segregation between larval plethodontid salamanders in replicate contact zones
<p>Contact zones present unique opportunities to investigate ecological divergence, reproductive barriers, and gene flow between species. The two-lined salamander (<em>Eurycea</em> <em>bislineata</em>) species complex is a group of semiaquatic plethodontid salamanders with a reticulate evolutionary history that reflects the reorganization of river drainage basins. Although evidence for widespread, ancient introgression suggests an absence of reproductive isolating mechanisms in the early evolutionary history of the group, modern contact zones reveal a broader diversity of outcomes—with some putative species pairs occurring in sympatry and others exhibiting narrow hybrid zones. Here, we used RADcap data to investigate gene flow and ecological divergence in replicate contact zones between two species in the Appalachian foothills. Our results demonstrate that gene flow between these species is absent or rare, and larvae show strong, fine-scale ecological segregation among riffles, runs, and pools in streams. These results reinforce the more ambiguous conclusions of previous studies that suggested the evolutionary distinctiveness of these two species and underscore the importance of ecological factors in shaping local distributions.</p>
Data from: Experimental contact zones reveal causes and targets of sexual selection in hybridizing lizards
Divergence in sexually selected traits in allopatry should affect the degree and direction of hybridization. However, few studies have established the causes and targets of sexual selection during secondary contact. Common wall lizards (Podarcis muralis) from north-central Italy have highly exaggerated male sexual traits compared to populations in Western Europe. Using experimental populations, we show that this creates asymmetries in male dominance, spatial habitat use and reproductive success upon secondary contact. Hybridization occurred almost exclusively between males of the Italian lineage and females of the Western European lineage. We provide evidence to suggest stronger ongoing selection on male sexual traits within the dominant Italian lineage. However, these same characters did not predict hybridization, and hybrid matings contributed little to variance in male reproductive success. Instead, most hybrid offspring were sired by Italian males displaying phenotypes associated with lower within-lineage reproductive success. Thus, highly directional hybridization arises because some Italian males are out-competed within their own lineage but remain competitive relative to males of the other lineage. This pattern of hybridization is consistent with the direction of introgression in natural contact zones, but our data suggest that sexual selection acting through hybridization may be weak at the leading edge of natural hybrid zones.
Data from: Selection on outlier loci and their association with adaptive phenotypes in Littorina saxatilis contact zones
A fundamental issue in speciation research is to evaluate phenotypic variation and the genomics driving the evolution of reproductive isolation between sister taxa. Above all, hybrid zones are excellent study systems for researchers to examine the association of genetic differentiation, phenotypic variation and the strength of selection. We investigated two contact zones in the marine gastropod Littorina saxatilis and utilized landmark-based geometric morphometric analysis together with amplified fragment length polymorphism (AFLP) markers to assess phenotypic and genomic divergence between ecotypes under divergent selection. From genetic markers, we calculated the cline width, linkage disequilibrium and the average effective selection on a locus. Additionally, we conducted an association analysis linking the outlier loci and phenotypic variation between ecotypes and show that a proportion of outlier loci are associated with key adaptive phenotypic traits.
Data from: Sperm divergence in a passerine contact zone: indication of reinforcement at the gametic level
Postcopulatory sexual selection may promote evolutionary diversification in sperm form, but the contribution of between-species divergence in sperm morphology to the origin of reproductive isolation and speciation remains little understood. To assess the possible role of sperm diversification in reproductive isolation, we studied sperm morphology in two closely related species, the common nightingale (Luscinia megarhynchos) and the thrush nightingale (L. luscinia), that hybridize in a secondary contact zone spanning Central and Eastern Europe. We found: (1) striking divergence between the species in total sperm length, accompanied by a difference in the length of the mitochondrial sperm component; (2) greater divergence between species in sperm morphology in sympatry than in allopatry, with evidence for character displacement in sperm head length detected in L. megarhynchos; (3) interspecific hybrids showing sperm with a length intermediate between the parental species, but no evidence for decreased sperm quality (the proportion of abnormal spermatozoa in ejaculates). Our results demonstrate that divergence in sperm morphology between the two nightingale species does not result in intrinsic postzygotic isolation, but may contribute to postcopulatory prezygotic isolation. This isolation could be strengthened in sympatry by reinforcement.
Data from: Assessing reproductive isolation using a contact zone between parapatric lake-stream stickleback ecotypes
Ecological speciation occurs when populations evolve reproductive isolation as a result of divergent natural selection. This isolation can be influenced by many potential reproductive barriers, including selection against hybrids, selection against migrants, and assortative mating. How and when these barriers act and interact in nature is understood for relatively few empirical systems. We used a mark-recapture experiment in a contact zone between lake and stream three-spined sticklebacks (Gasterosteus aculeatus, Linnaeus) to evaluate the occurrence of hybrids (allowing inferences about reproductive isolation), the inter-annual survival of hybrids (allowing inferences about selection against hybrids), and the shift in lake-like versus stream-like characteristics (allowing inferences about selection against migrants). Genetic and morphological data suggest the occurrence of hybrids and no selection against hybrids in general, a result contradictory to a number of other studies of sticklebacks. However, we did find selection against more lake-like individuals, suggesting a barrier to gene flow from the lake into the stream. Combined with previous work on this system, our results suggest that multiple (most weakly and often asymmetric) barriers must be combining to yield substantial restrictions on gene flow. This work provides evidence of a reproductive barrier in lake-stream sticklebacks and highlights the value of assessing multiple reproductive barriers in natural contexts.
Fig. 10 in Introgression at the emerging secondary contact zone of magpie Pica pica subspecies (Aves: Corvidae): integrating data on nuclear and mitochondrial markers, vocalizations, and field observations
Fig. 10 Spectrograms of chatter calls of pure P. p. leucoptera, pure P. p. jankowskii, and hybrids. a leucoptera, pair #4, Choibalsan, eastern Mongolia. b jankowskii, pair #6, Vladivostok, Russian Far East. c, d Bilingual hybrid, the same bird from the pair #24, Kerulen, eastern Mongolia. e Hybrid with mixed call, pair #39, Kerulen. f Presumably hybrid with mixed call, pair #5, Kerulen. X-axis—time in s; Y-axis—frequency in kHz
Fig. 8 in Introgression at the emerging secondary contact zone of magpie Pica pica subspecies (Aves: Corvidae): integrating data on nuclear and mitochondrial markers, vocalizations, and field observations
Fig. 8 Genetic structure of the contact zone and its vicinities by mtDNA and SNPs. Above—distribution of haplotypes of mitochondrial CR along conditional population numbers I–VI depicted in Fig. 3. Green—western haplotype; red—eastern haplotype. Below— graphical representation of individual contributions from nuclear
Fig. 3 in Introgression at the emerging secondary contact zone of magpie Pica pica subspecies (Aves: Corvidae): integrating data on nuclear and mitochondrial markers, vocalizations, and field observations
Fig. 3 Map of sampling localities for nuclear SNP analysis. Distribution of genotypes of nuclear SNPs revealed by ddRAD analysis are shown with blue circles for Pica pica leucoptera and red circles for Pica pica jankowskii. Bi-colored circles mean mixed (hybrid) genotype: portion of blue/red corresponds to probability of it belonging to one of the groups, as revealed in the Structure analysis. Numbers
Fig. 1 in Introgression at the emerging secondary contact zone of magpie Pica pica subspecies (Aves: Corvidae): integrating data on nuclear and mitochondrial markers, vocalizations, and field observations
Fig. 1 Map of Pica pica s.l. subspecies. The study area in the contact zone is indicated by a rectangle. Question marks indicate regions of unclear subspecies distribution. The white star indicates the terra typica for Pica pica anderssoni in eastern China
Data from: Revisiting the Iberian honey bee (Apis mellifera iberiensis) contact zone: maternal and genome-wide nuclear variation provide support for secondary contact from historical refugia
Dissecting diversity patterns of organisms endemic to Iberia has been truly challenging for a variety of taxa, and the Iberian honey bee is no exception. Surveys of genetic variation in the Iberian honey bee are among the most extensive for any honey bee subspecies. From these, differential and complex patterns of diversity have emerged, which have yet to be fully resolved. Here, we used a genome-wide data set of 309 neutrally tested single nucleotide polymorphisms (SNPs), scattered across the 16 honey bee chromosomes, which were genotyped in 711 haploid males. These SNPs were analysed along with an intergenic locus of the mtDNA, to reveal historical patterns of population structure across the entire range of the Iberian honey bee. Overall, patterns of population structure inferred from nuclear loci by multiple clustering approaches and geographic cline analysis were consistent with two major clusters forming a well-defined cline that bisects Iberia along a northeastern–southwestern axis, a pattern that remarkably parallels that of the mtDNA. While a mechanism of primary intergradation or isolation by distance could explain the observed clinal variation, our results are more consistent with an alternative model of secondary contact between divergent populations previously isolated in glacial refugia, as proposed for a growing list of other Iberian taxa. Despite current intense honey bee management, human-mediated processes have seemingly played a minor role in shaping Iberian honey bee genetic structure. This study highlights the complexity of the Iberian honey bee patterns and reinforces the importance of Iberia as a reservoir of Apis mellifera diversity.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
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DANDI Archive for NWB datasets
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