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4,480 results for “hybrid”
Data from: Characterising a hybrid zone between a cryptic species pair of freshwater snails
Characterising hybrid zones and their dynamics is a central goal in evolutionary biology, but this is particularly challenging for morphologically cryptic species. The lack of conspicuous divergence between parental types means intermediate hybrid forms often go undetected. We aimed to detect and characterise a suspected hybrid zone between a pair of morphologically cryptic lineages of the freshwater snail, Radix. We sampled Radix from across a contact zone between two mitochondrial lineages (Radix balthica and an undescribed lineage termed MOTU3) and detected admixture between two nuclear genotype clusters, which were significantly but not categorically associated with the mitochondrial lineages. In a model selection approach, we show that the admixture cline is best explained by an interaction between precipitation and temperature gradients over the area, rather than geographic distance. We thus hypothesise that the correlation with climatic gradients suggests environmental selection has played a role in maintaining the hybrid zone. In a 2050 climate change scenario, we furthermore predict an expansion of one of the nuclear clusters and a widening of the hybrid zone as the climate warms and dries.
Data from: Differential introgression across newt hybrid zones – evidence from replicated transects
<p>Genomic heterogeneity of divergence between hybridizing species may reflect heterogeneity of introgression, but also processes unrelated to hybridization. Heterogeneous introgression and its repeatability can be directly tested in natural hybrid zones by examining multiple transects. Here, we studied hybrid zones between the European newts: Lissotriton montandoni and two lineages of L. vulgaris, with replicate transects within each zone. Over 1000 nuclear genes located on a linkage map and mtDNA were investigated using geographic and genomic clines. Overall, the five transects were all similar, showing hallmarks of strong reproductive isolation: bimodal distribution of genotypes in central populations and narrow allele frequency clines. However, the extent of introgression differed between the zones, likely as a consequence of their different ages, indicated by the analysis of heterozygosity runs in diagnostic markers. In three transects genomic signatures of small-scale (ca. 2 km) zone movements were detected. We found a limited overlap of cline outliers between transects, and no evidence of stronger differentiation between zones than between transects within zones. Introgression was heterogeneous across linkage groups, with patterns of heterogeneity similar between transects and zones. Predefined candidates for increased or reduced introgression exhibited only a subtle tendency in the expected direction, suggesting that interspecific differentiation is not a reliable indicator for the strength of introgression. These hierarchically sampled hybrid zones of different ages show how introgression unfolds with time and offer an excellent opportunity to dissect the dynamics of hybridization and architecture of reproductive isolation at advanced stages of speciation.</p>
Data from: Admixture mapping of quantitative traits in Populus hybrid zones: power and limitations
Uncovering the genetic architecture of species differences is of central importance for understanding the origin and maintenance of biological diversity. Admixture mapping can be used to identify the number and effect sizes of genes that contribute to the divergence of ecologically important traits, even in taxa that are not amenable to laboratory crosses due to their long generation time or other limitations. Here, we apply admixture mapping to naturally occurring hybrids between two ecologically divergent Populus species. We map quantitative trait loci (QTL) for eight leaf morphological traits using 77 mapped microsatellite markers from all 19 chromosomes of Populus. We apply multivariate linear regression analysis allowing the modeling of additive and non-additive gene action and identify several candidate genomic regions associated with leaf morphology using an information-theoretic approach. We perform simulation studies to assess the power and limitations of admixture mapping of quantitative traits in natural hybrid populations for a variety of genetic architectures and modes of gene action. Our results indicate that (1) admixture mapping has considerable power to identify the genetic architecture of species differences if sample sizes and marker densities are sufficiently high, (2) modeling of non-additive gene action can help to elucidate the discrepancy between genotype and phenotype sometimes seen in interspecific hybrids, and (3) the genetic architecture of leaf morphological traits in the studied Populus species involves complementary and overdominant gene action, providing the basis for rapid adaptation of these ecologically important forest trees.
Genetic structure in hybrids and progenitors provides insight into processes underlying an invasive cattail (Typha x glauca) hybrid zone
<p>Traditional models of hybrid zones have assumed relatively low hybrid fitness, and thus focussed more on interspecific gene flow than on hybrid dispersal. Therefore, when hybrids have high fitness and the potential for autonomous dispersal, we have limited understanding of whether hybrid dispersal or repeated local hybrid formation is more important for maintaining hybrid zones. The invasive hybrid cattail <i>Typha × glauca</i> occupies an extensive hybrid zone in northeastern North America where it is sympatric with its progenitors <i>T. latifolia</i> and <i>T. angustifolia</i>. We characterized genetic diversity and genetic structure of the three taxa across a broad spatial scale, and tested the hypothesis that the hybrid shows stronger evidence of gene flow than its progenitor species, particularly among disturbed sites (ditches) compared to established wetlands. Support for this hypothesis would suggest that dispersal, rather than repeated local formation, is more important in maintaining hybrid zones. Within each taxon, genetic differentiation among ditches was comparable to that among wetlands, although clonal richness was consistently greater in ditches suggesting more frequent seed establishment. Genetic structure across sites was more pronounced in the hybrid compared to either progenitor species. Overall, our data reflect relatively low gene flow in hybrids, and suggest that hybrids are more likely to be created <i>in situ</i> than to be introduced from other sites. Despite the high fitness of invasive <i>T. </i>× <i>glauca </i>and its potential for autonomy<i>, </i>local processes appear more important than dispersal in maintaining this hybrid zone.</p>
Data from: Immigrant and extrinsic hybrid inviability contribute to reproductive isolation between lake and river cichlid ecotypes
Understanding how reproductive barriers evolve and which barriers contribute to speciation requires the examination of organismal lineages that are still in the process of diversification and the study of the full range of reproductive barriers acting at different life stages. Lake and river ecotypes of the East African cichlid fish Astatotilapia burtoni show habitat specific adaptations, despite different levels of genetic differentiation, and thus represent an ideal model to study the evolution of reproductive barriers. To evaluate the degree of reproductive isolation between genetically divergent lake and river populations, we performed a mesocosm mating experiment in a semi-natural setting at Lake Tanganyika. We assessed reproductive isolation in the presence of male–male competition by analysing survival and growth rates of introduced adults and their reproductive success from genetic parentage of surviving offspring. The genetically divergent river population showed reduced fitness in terms of survival, growth rate, and mating success in a lake-like environment. Hybrid offspring between different populations showed intermediate survival consistent with extrinsic postzygotic reproductive barriers. Our results suggest that both prezygotic (immigrant inviability) and postzygotic reproductive barriers contribute to divergence, and highlight the value of assessing multiple reproductive barriers acting at different stages and in natural contexts to understand speciation mechanisms.
Data from: Successive invasion-mediated interspecific hybridizations and population structure in the endangered cichlid Oreochromis mossambicus
Hybridization between invasive and native species accounts among the major and pernicious threats to biodiversity. The Mozambique tilapia Oreochromis mossambicus, a widely used freshwater aquaculture species, is especially imperiled by this phenomenon since it is recognized by the IUCN as an endangered taxon due to genetic admixture with O. niloticus an invasive congeneric species. The Lower Limpopo and the intermittent Changane River (Mozambique) drain large wetlands of potentially great importance for conservation of O. mossambicus, but their populations have remained unstudied until today. Therefore we aimed (1) to estimate the autochthonous diversity and population structure among genetically pure O. mossambicus populations to provide a baseline for the conservation genetics of this endangered species, (2) to quantify and describe genetic variation of the invasive populations and investigate the most likely factors influencing their spread, (3) to identify O. mossambicus populations unaffected by hybridization. Bayesian assignment tests based on 423 AFLP loci and the distribution of 36 species-specific mitochondrial haplotypes both indicate a low frequency of invasive and hybrid genotypes throughout the system, but nevertheless reveal evidence for limited expansion of two alien species (O. niloticus and O. andersonii) and their hybrids in the Lower Limpopo. O. mossambicus populations with no traces of hybridization are identified. They exhibit a significant genetic structure. This contrasts with previously published estimates and provides rather promising auspices for the conservation of O. mossambicus. Especially, parts of the Upper Changane drainage and surrounding wetlands are identified as refugial zones for O. mossambicus populations. They should therefore receive high conservation priority and could represent valuable candidates for the development of aquaculture strains based on local genetic resources.
Data from: Integrating molecular, phenotypic and environmental data to elucidate patterns of crocodile hybridization in Belize
The genus Crocodylus comprises 12 currently recognized species, many of which can be difficult to differentiate phenotypically. Interspecific hybridization among crocodiles is known to occur in captivity and has been documented between some species in the wild. The identification of hybrid individuals is of importance for management and monitoring of crocodilians, many of which are Convention on International Trade in Endangered Species (CITES) listed. In this study, both mitochondrial and nuclear DNA markers were evaluated for their use in confirming a suspected hybrid zone between American crocodile (Crocodylus acutus) and Morelet's crocodile (Crocodylus moreletii) populations in southern Belize where individuals and nests exhibiting atypical phenotypic features had previously been observed. Patterns observed in both phenotypic and molecular data indicate possible behavioural and ecological characteristics associated with hybridization events. The results of the combined analyses found that the majority of suspected hybrid samples represent crosses between female C. acutus and male C. moreletii. Phenotypic data could statistically identify hybrids, although morphological overlap between hybrids and C. moreletii reduced reliability of identification based solely on field characters. Ecologically, C. acutus was exclusively found in saline waters, whereas hybrids and C. moreletii were largely absent in these conditions. A hypothesized correlation between unidirectional hybridization and destruction of C. acutus breeding habitats warrants additional research.
Data from: Bone-to-body biometric relationships for Owens and Lahontan tui chubs and their hybrids in California
Regression parameters for the length of several bony structures against fish body length, and for body length against body weight, were determined for Owens tui chub (Siphateles bicolor snyderi), Lahontan tui chub (S. b. obesa) and hybrid swarm deriving from the two species. A total of 211 individuals from 16 localities from the Owens River and neighboring basins along the border between California and Nevada were used for regression analyses. The coefficient of determination of linear regressions for scales, pharyngeal arches, dentaries, cleithra, and opercula against body length were consistently high (r2 埲.9). Differences between subspecies were mainly with reference to the intercept parameter in comparisons involving Lahontan tui chub. Coefficients of determination from log-linear length-weight regressions were also high (r2 埲.9) for individual taxa and for the pooled data set combining both Lahontan and hybrid species. The length-weight relation ship did not differ between subspecies. Estimates of the length-weight relationship using data pooling both Lahontan and hybrid tui chub suggest a weak allometric growth effect (P<0.05). The bone-length to body-length and body-length to body-weight relationships presented here will be useful tools for future dietary studies of tui chub predators as well as for archaeological and paleontological studies on tui chub remains.
Data from: Hybrid breakdown weakens under thermal stress in population crosses of the copepod Tigriopus californicus.
The outcome of hybridization can be impacted by environment conditions, which themselves can contribute to reproductive isolation between taxa. In crosses of genetically divergent populations, hybridization can have both negative and positive impacts on fitness, the balance between which might be tipped by changes in the environment. Genetically divergent populations of the intertidal copepod Tigriopus californicus have been shown to differ in thermal tolerance at high temperatures along a latitudinal gradient. In this study a series of crosses were made between pairs of genetically divergent populations of T. californicus and the thermal tolerance of these hybrids was tested. In most cases the first generation hybrids had relatively high thermal tolerance and second generation hybrids were not generally reduced below the less-tolerant parental population for high temperature tolerance. This pattern contrasts with previous studies from crosses of genetically divergent populations of this copepod which often show hybrid breakdown in these second generation hybrids for other measures of fitness. These results suggest that high temperature stress could either increase the positive impacts of hybridization or decrease the negative impacts of hybridization resulting in lowered hybrid breakdown in these population crosses.
Data from: Detecting hybridization by likelihood calculation of gene tree extra lineages given explicit models
Explanations for gene tree discordance with respect to a species tree are commonly attributed to deep coalescence (also known as incomplete lineage sorting [ILS]), as well as different evolutionary processes such as hybridization, horizontal gene transfer and gene duplication. Among these, deep coalescence is usually quantified as the number of extra lineages and has been studied as the principal source of discordance among gene trees, while the other processes that could contribute to gene tree discordance have not been fully explored. This is an important issue for hybridization because interspecific gene flow is well documented and widespread across many plant and animal groups. Here, we propose a new way to detect gene flow when ILS is present that evaluates the likelihood of different models with various levels of gene flow, by comparing the expected gene tree discordance, using the number of extra lineages. This approach consists of proposing a model, simulating a set of gene trees to infer a distribution of expected extra lineages given the model, and calculating a likelihood function by comparing the fit of the real gene trees to the simulated distribution. To count extra lineages, the gene tree is first reconciled within the species tree, and for a given species tree branch the number of gene lineages minus one is counted. We develop a set of R functions to parallelize software to allow simulations, and to compare hypotheses via a likelihood ratio test to evaluate the presence of gene flow when ILS is present, in a fast and simple way. Our results show high accuracy under very challenging scenarios of high impact of ILS and low gene flow levels, even using a modest dataset of five to ten loci and five to ten individuals per species. We present a powerful and fast method to detect hybridization in presence of ILS. We discuss its advantage with large dataset (such as genomic scale), and also identifies possible issues that should be explored with more complex models in future studies.
Data from: Genome-wide mapping in a house mouse hybrid zone reveals hybrid sterility loci and Dobzhansky-Muller interactions
Mapping hybrid defects in contact zones between incipient species can identify genomic regions contributing to reproductive isolation and reveal genetic mechanisms of speciation. The house mouse features a rare combination of sophisticated genetic tools and natural hybrid zones between subspecies. Male hybrids often show reduced fertility, a common reproductive barrier between incipient species. Laboratory crosses have identified sterility loci, but each encompasses hundreds of genes. We map genetic determinants of testis weight and testis gene expression using offspring of mice captured in a hybrid zone between M. musculus musculus and M. m. domesticus. Many generations of admixture enables high-resolution mapping of loci contributing to these sterility-related phenotypes. We identify complex interactions among sterility loci, suggesting multiple, non-independent genetic incompatibilities contribute to barriers to gene flow in the hybrid zone.
Data from: Anchored hybrid enrichment provides new insights into the phylogeny and evolution of longhorned beetles (Cerambycidae)
Cerambycidae is a species-rich family of mostly wood-feeding (xylophagous) beetles containing nearly 35 000 known species. The higher-level phylogeny of Cerambycidae has never been robustly reconstructed using molecular phylogenetic data or a comprehensive sample of higher taxa, and its internal relationships and evolutionary history remain the subjects of ongoing debate. We reconstructed the higher-level phylogeny of Cerambycidae using phylogenomic data from 522 single copy nuclear genes, generated via anchored hybrid enrichment. Our taxon sample (31 Chrysomeloidea, four outgroup taxa: two Curculionoidea and two Cucujoidea) included exemplars of all families and 23 of 30 subfamilies of Chrysomeloidea (18 of 19 non-chrysomelid Chrysomeloidea), with a focus on the large family Cerambycidae. Our results reveal a monophyletic Cerambycidae s.s. in all but one analysis, and a polyphyletic Cerambycidae s.l. When monophyletic, Cerambycidae s.s. was sister to the family Disteniidae. Relationships among the subfamilies of Cerambycidae s.s. were also recovered with strong statistical support except for Cerambycinae being made paraphyletic by Dorcasomus Audinet-Serville (Dorcasominae) in the nucleotide (but not amino acid) trees. Most other chrysomeloid families represented by more than one terminal taxon – Chrysomelidae, Disteniidae, Vesperidae and Orsodacnidae – were monophyletic, but Megalopodidae was rendered paraphyletic by Cheloderus Gray (Oxypeltidae). Our study corroborates some relationships within Chrysomeloidea that were previously inferred from morphological data, while also reporting several novel relationships. The present work thus provides a robust framework for future, more deeply taxon-sampled, phylogenetic and evolutionary studies of the families and subfamilies of Cerambycidae s.l. and other Chrysomeloidea.
Data from: Demography and speciation history of the homoploid hybrid pine Pinus densata on the Tibetan Plateau
Pinus densata is an ecologically successful homoploid hybrid that inhabits vast areas of heterogeneous terrain on the southeastern Tibetan Plateau as a result of multiple waves of colonization. Its region of origin, route of colonization onto the plateau and the directions of introgression with its parental species have previously been defined, but little is known about the isolation and divergence history of its populations. In this study, we surveyed nucleotide polymorphism over eight nuclear loci in 19 representative populations of P. densata and its parental species. Using this information and coalescence simulations, we assessed the historical changes in its population size, gene flow, and divergence in time and space. The results indicate a late Miocene origin for P. densata associated with the recent uplift of southeastern Tibet. The subsequent differentiation between geographical regions of this species began in the late Pliocene and was induced by regional topographic changes and Pleistocene glaciations. The ancestral P. densata population had a large effective population size but the central and western populations were established by limited founders, suggesting that there were severe bottlenecks during the westward migration out of the ancestral hybrid zone. After separating from their ancestral populations, population expansion occurred in all geographic regions especially in the western range. Gene flow in P. densata was restricted to geographically neighboring populations, resulting in significant differentiation between regional groups. The new information on the divergence and demographic history of P. densata reported herein enhances our understanding of its speciation process on the Tibetan Plateau.
Data from: Landscape genomics of Populus trichocarpa: the role of hybridization, limited gene flow and natural selection in shaping patterns of population structure
Populus trichocarpa is an ecologically important tree across western North America. We used a large population sample of 498 accessions over a wide geographical area genotyped with a 34K Populus SNP array to quantify geographical patterns of genetic variation in this species (landscape genomics). We present evidence that three processes contribute to the observed patterns: (1) introgression from the sister species P. balsamifera (2) isolation-by-distance and (3) natural selection. Introgression was detected only at the margins of the species' distribution. Isolation-by-distance was significant across the sampled area as a whole, but no evidence of restricted gene flow was detected in a core of drainages from southern British Columbia. We identified a large number of FST outliers. GO analyses revealed that FST outliers are overrepresented in genes involved in circadian rhythm and response to red/far-red light when the entire dataset is considered, while in southern British Columbia heat response genes are overrepresented. We also identified strong correlations between geoclimate variables and allele frequencies at FST outlier loci that provide clues regarding the selective pressures acting at these loci.
Persistence of an endangered native duck, feral mallards, and multiple hybrid swarms across the main Hawaiian Islands
Interspecific hybridization is recognized as an important process in the evolutionary dynamics of both speciation and the reversal of speciation. However, our understanding of the spatial and temporal patterns of hybridization that erode versus promote species boundaries is incomplete. The endangered, endemic koloa maoli (or Hawaiian duck, Anas wyvilliana) is thought to be threatened with genetic extinction through ongoing hybridization with an introduced congener, the feral mallard (A. platyrhynchos). We investigated spatial and temporal variation in hybrid prevalence in populations throughout the main Hawaiian Islands, using genomic data to characterize population structure of koloa, quantify the extent of hybridization, and compare hybrid proportions over time. To accomplish this, we genotyped 3,308 double-digest restriction-site-associated DNA (ddRAD) loci in 425 putative koloa, mallards, and hybrids from populations across the main Hawaiian Islands. We found that despite a population decline in the last century, koloa genetic diversity is high. There were few hybrids on the island of Kauaʻi, home to the largest population of koloa. By contrast, we report that sampled populations outside of Kauaʻi can now be characterized as hybrid swarms, in that all individuals sampled were of mixed koloa × mallard ancestry. Further, there is some evidence that these swarms are stable over time. These findings demonstrate spatial variation in the extent and consequences of interspecific hybridization, and highlight how islands or island-like systems with small population sizes may be especially prone to genetic extinction when met with a congener that is not reproductively isolated.
Data from: A wood-warbler produced through both interspecific and intergeneric hybridization
Hybridization between divergent taxa can provide insight into the breakdown of characters used in mate choice, as well as reproductive compatibility across deep evolutionary timescales. Hybridization can also occur more frequently in declining populations, as there is a smaller pool of conspecific mates from which to choose. Here we report an unusual combination of factors that has resulted in a rare, three-species hybridization event amongst two genera of warblers, one of which is experiencing significant population declines. We use bioacoustic, morphometric, and genetic data, to demonstrate that an early generation female hybrid between a golden-winged warbler (Vermivora chrysoptera) and a blue-winged warbler (V. cyanoptera) went on to mate and successfully reproduce with a chestnut-sided warbler (Setophaga pensylvanica). We studied the product of this event—a putative chrysoptera x cyanoptera x pensylvanica hybrid—and show that this male offspring sang songs like S. pensylvanica, but had morphometric traits similar to Vermivora warblers. The hybrid's maternal parent had V. chrysoptera mitochondrial DNA and, with six plumage-associated loci, we predicted the maternal parent's phenotype to show that it was likely an early generation Vermivora hybrid. That this hybridization event occurred within a population of Vermivora warblers in significant decline suggests that females may be making the best of a bad situation, and that wood-warblers in general have remained genetically compatible long after they evolved major phenotypic differences.
Data from: Strongly asymmetric hybridization barriers shape the origin of a new polyploid species and its hybrid ancestor
PREMISE OF THE STUDY: Hybridization between diploids and tetraploids can lead to new allopolyploid species, often via a triploid intermediate. Viable triploids are often produced asymmetrically, with greater success observed for "maternal-excess" crosses where the mother has a higher ploidy than the father. Here we investigated the evolutionary origins of Mimulus peregrinus, an allohexaploid recently derived from the triploid M. ×robertsii, to determine whether reproductive asymmetry has shaped the formation of this new species. METHODS: We used reciprocal crosses between the diploid (M. guttatus) and tetraploid (M. luteus) progenitors to determine the viability of triploid M. ×robertsii hybrids resulting from paternal- vs. maternal-excess crosses. To investigate whether experimental results predict patterns seen in the field, we performed parentage analyses comparing natural populations of M. peregrinus to its diploid, tetraploid, and triploid progenitors. Organellar sequences obtained from pre-existing genomic data, supplemented with additional genotyping was used to establish the maternal ancestry of multiple M. peregrinus and M. ×robertsii populations. KEY RESULTS: We found strong evidence for asymmetric origins of M. peregrinus, but opposite to the common pattern, with paternal-excess crosses significantly more successful than maternal-excess crosses. These results successfully predicted hybrid formation in nature: 111 of 114 M. ×robertsii individuals, and 27 of 27 M. peregrinus, had an M. guttatus maternal haplotype. CONCLUSION: This study, which includes the first Mimulus chloroplast genome assembly, demonstrates the utility of parentage analysis through genome skimming. We highlight the benefits of complementing genomic analyses with experimental approaches to understand asymmetry in allopolyploid speciation.
Data from: A hybrid phylogenetic–phylogenomic approach for species tree estimation in African Agama lizards with applications to biogeography, character evolution, and diversification
Africa is renowned for its biodiversity and endemicity, yet little is known about the factors shaping them across the continent. African Agama lizards (45 species) have a pan-continental distribution, making them an ideal model for investigating biogeography. Many species have evolved conspicuous sexually dimorphic traits, including extravagant breeding coloration in adult males, large adult male body sizes, and variability in social systems among colorful versus drab species. We present a comprehensive time-calibrated species tree for Agama, and their close relatives, using a hybrid phylogenetic-phylogenomic approach that combines traditional Sanger sequence data from five loci for 57 species (146 samples) with anchored phylogenomic data from 215 nuclear genes for 23 species. The Sanger data are analyzed using coalescent-based species tree inference using *BEAST, and the resulting posterior distribution of species trees is attenuated using the phylogenomic tree as a backbone constraint. The result is a time-calibrated species tree for Agama that includes 95% of all species, multiple samples for most species, strong support for the major clades, and strong support for most of the initial divergence events. Diversification within Agama began approximately 23 million years ago (Ma), and separate radiations in Southern, East, West, and Northern Africa have been diversifying for > 10 Myr. A suite of traits (morphological, coloration, and sociality) are tightly correlated and show a strong signal of high morphological disparity within clades, whereby the subsequent evolution of convergent phenotypes has accompanied diversification into new biogeographic areas.
Data from: Bayesian analysis of hybridization and introgression between the endangered european mink (Mustela lutreola) and the polecat (Mustela putorius)
Human-mediated global change will probably increase the rates of natural hybridization and genetic introgression between closely related species, and this will have major implications for conservation of the taxa involved. In this study, we analyse both mitochondrial and nuclear data to characterize ongoing hybridization and genetic introgression between two sympatric sister species of mustelids, the endangered European mink (Mustela lutreola) and the more abundant polecat (M. putorius). A total of 317 European mink, 114 polecats and 15 putative hybrid individuals were collected from different localities in Europe and genotyped with 13 microsatellite nuclear markers. Recently developed Bayesian methods for assigning individuals to populations and identifying admixture proportions were applied to the genetic data. To identify the direction of hybridization, we additionally sequenced mtDNA and Y chromosomes from 78 individuals and 29 males respectively. We found that both hybridization and genetic introgression occurred at low levels (3% and 0.9% respectively) and indicated that hybridization is asymmetric, as only pure polecat males mate with pure European mink females. Furthermore, backcrossing and genetic introgression was detected only from female first-generation (F1) hybrids of European mink to polecats. This latter result implies that Haldane's rule may apply. Our results suggest that hybridization and genetic introgression between the two species should be considered a rather uncommon event. However, the current low densities of European mink might be changing this trend.
Data from: Asymmetric energetic costs in reciprocal-cross hybrids between carnivorous mice (Onychomys)
Aerobic respiration is a fundamental physiological trait dependent on coordinated interactions between gene products of the mitochondrial and nuclear genomes. Mitonuclear mismatch in interspecific hybrids may contribute to reproductive isolation by inducing reduced viability (or even complete inviability) due to increased metabolic costs. However, few studies have tested for effects of mitonuclear mismatch on respiration at the whole organism level. We explored how hybridization affects metabolic rates in closely related species of grasshopper mice (genus Onychomys) to better understand the role of metabolic costs in reproductive isolation. We measured metabolic rate across a range of temperatures to calculate basal metabolic rates (BMR) and cold-induced metabolic rates (MRc) in O. leucogaster, O. torridus, and O. arenicola, and in reciprocal F1 hybrids between the latter two species. Within the genus, we found a negative correlation between mass-specific BMR and body mass. Although O. arenicola was smaller than O. torridus, hybrids from both directions of the cross resembled O. arenicola in body mass. In contrast, hybrid BMR was strongly influenced by the direction of the cross: reciprocal F1 hybrids were different from each other but indistinguishable from the maternal species. In addition, MRc was not significantly different between hybrids and either parental species. These patterns indicate that metabolic costs are not increased in Onychomys F1 hybrids and, while exposure of incompatibilities in F2 hybrids cannot be ruled out, suggests that mitonuclear mismatch does not act as a primary barrier to gene flow. Maternal matching of BMR is suggestive of a strong effect of mitochondrial genotype on metabolism in hybrids. Together, our findings provide insight into the metabolic consequences of hybridization, a topic that is understudied in mammals.
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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)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.