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1.
Zootaxa ; 4852(5): zootaxa.4852.5.8, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-33056400

RESUMO

Anuran calls are conspicuous, diverse and subject to sexual selection. Many types of calls are described, but the most commonly studied is the advertisement call (Wells 2007; Toledo et al. 2014). Advertisement calls in anurans are emitted by males and some females (Toledo et al. 2014), and have the function of attracting conspecific mates and repelling male competitors. Because the advertisement calls of many species differ by such a magnitude that they serve as premating species (Heyer et al. 1996), it has been demonstrated that advertisement calls play an important role in species recognition, reproductive isolation, and may reflect evolutionary relations among taxa (Wells 2007; Escalona et al. 2018).


Assuntos
Anuros , Vocalização Animal , Animais , Evolução Biológica , Colômbia , Feminino , Masculino , Isolamento Reprodutivo
3.
BMC Evol Biol ; 20(1): 110, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32847507

RESUMO

BACKGROUND: Island systems offer excellent opportunities for studying the evolutionary histories of species by virtue of their restricted size and easily identifiable barriers to gene flow. However, most studies investigating evolutionary patterns and processes shaping biotic diversification have focused on more recent (emergent) rather than ancient oceanic archipelagos. Here, we focus on the granitic islands of the Seychelles, which are unusual among island systems because they have been isolated for a long time and are home to a monophyletic radiation of caecilian amphibians that has been separated from its extant sister lineage for ca. 65-62 Ma. We selected the most widespread Seychelles caecilian species, Hypogeophis rostratus, to investigate intraspecific morphological and genetic (mitochondrial and nuclear) variation across the archipelago (782 samples from nine islands) to identify patterns and test processes that shaped their evolutionary history within the Seychelles. RESULTS: Overall a signal of strong geographic structuring with distinct northern- and southern-island clusters were identified across all datasets. We suggest that these distinct groups have been isolated for ca. 1.26 Ma years without subsequent migration between them. Populations from the somewhat geographically isolated island of Frégate showed contrasting relationships to other islands based on genetic and morphological data, clustering alternatively with northern-island (genetic) and southern-island (morphological) populations. CONCLUSIONS: Although variation in H. rostratus across the Seychelles is explained more by isolation-by-distance than by adaptation, the genetic-morphological incongruence for affinities of Frégate H. rostratus might be caused by local adaptation over-riding the signal from their vicariant history. Our findings highlight the need of integrative approaches to investigate fine-scale geographic structuring to uncover underlying diversity and to better understand evolutionary processes on ancient, continental islands.


Assuntos
Anfíbios , Fluxo Gênico , Variação Genética , Genética Populacional , Anfíbios/genética , Animais , Evolução Biológica , Ilhas , Filogenia , Isolamento Reprodutivo , Seicheles
4.
Bull Entomol Res ; 110(6): 684-693, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32741378

RESUMO

For a wide range of insect species, the microbiota has potential roles in determining host developmental programme, immunity and reproductive biology. The tea geometrid moths Ectropis obliqua and E. grisescens are two closely related species that mainly feed on tea leaves. Although they can mate, infertile hybrids are produced. Therefore, these species provide a pair of model species for studying the molecular mechanisms of microbiotal involvement in host reproductive biology. In this study, we first identified and compared the compositions of microbiota between these sibling species, revealing higher microbiotal diversity for E. grisescens. The microbiota of E. obliqua mainly comprised the phyla Firmicutes, Proteobacteria and Cyanobacteria, whereas that of E. grisescens was dominated by Proteobacteria, Actinobacteria and Firmicutes. At the genus level, the dominant microbiota of E. grisescens included Wolbachia, Enterobacter and Pseudomonas and that of E. obliqua included Melissococcus, Staphylococcus and Enterobacter. Furthermore, we verified the rate of Wolbachia to infect 80 samples from eight different geographical populations, and the results supported that only E. grisescens harboured Wolbachia. Taken together, our findings indicate significantly different microbiotal compositions for E. obliqua and E. grisescens, with Wolbachia possibly being a curial factor influencing the reproductive isolation of these species. This study provides new insight into the mechanisms by which endosymbiotic bacteria, particularly Wolbachia, interact with sibling species.


Assuntos
Microbiota , Mariposas/microbiologia , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Feminino , Masculino , Isolamento Reprodutivo , Simbiose
5.
Evolution ; 74(8): 1883-1885, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32656771

RESUMO

Reproductive isolation can result from incompatibilities between mutations that arise in different individuals. Wang and Cooper examined this mechanism of postzygotic isolation in Escherichia coli experimentally evolved in either glucose or lactose. They formed recombinants from parents evolved in the same or different environments. Both same-environment and different-environment recombinants had lower fitness than the null expectation, but with important exceptions. These results indicate that the development of reproductive isolation is complex and results from incompatibilities that arise when populations are selected in either the same or different environment.


Assuntos
Escherichia coli , Isolamento Reprodutivo , Análise Custo-Benefício , Escherichia coli/genética , Humanos , Recombinação Genética
6.
PLoS One ; 15(7): e0235789, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645117

RESUMO

Eisenia andrei (Ea) and E. fetida (Ef) lumbricid earthworms are simultaneous hermaphrodites potentially capable of self-fertilization and hybridization. We have shown previously that reproductive isolation in these species is incomplete in Ea and Ef earthworms of French provenance, as viable offspring appeared in inter-specific pairs. Fertile asymmetric hybrids developed from Ea-derived ova fertilized by Ef-derived spermatozoa, as well as Ea or Ef specimens derived after self-fertilization (resulting from admixture of endogenously produced spermatozoa with sperm from a partner), but never Ef-hybrids from Ef-ova fertilized by Ea-spermatozoa. The latter appeared only in backcrosses of Ea-hybrids with the Ef. Here we show that these phenomena are not unique for French Ea/Ef earthworms, but are shared by earthworms from French, Hungarian, and Polish laboratory cultures. Semi-quantitative studies on fertility of Ea-derived hybrids revealed gradually decreasing numbers of offspring in three successive generations, more rapid in backcrosses with Ef than with Ea, and the absence of progeny in pairs of hybrids, despite the presence of cocoons in almost all pairs. Based on species specific mitochondrial and nuclear DNA sequences, we provide the first examples of two unique sterile hybrids with mitonuclear mismatch and potential mitonuclear incompatibility among offspring of one of the hybrid+Ef pairs. Earthworms from the investigated populations did not reproduce when kept from hatching in isolation or with representatives of Dendrobaena veneta but started reproducing upon recognition of a related partner, such as Ea, Ef or their hybrids. The existence of Ea or Ef specimens among offspring of hybrid+Ea/Ef pairs might be explained either by partner-induced self-fertilization of Ea/Ef or hybrid-derived ova, or by cross-fertilization of Ea/Ef /hybrid ova by partner-derived spermatozoa; the latter might contribute to interspecific gene introgression.


Assuntos
Oligoquetos/fisiologia , Animais , Feminino , Fertilidade , Fertilização , França , Hungria , Hibridização Genética , Masculino , Oligoquetos/genética , Polônia , Reprodução , Isolamento Reprodutivo , Especificidade da Espécie , Espermatozoides/metabolismo
7.
Ann Bot ; 126(6): 991-1003, 2020 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-32353869

RESUMO

BACKGROUND AND AIMS: Polyploidy is an important contributor to sympatric speciation and assortative mating is a key mechanism driving cytotype interactions in contact zones. While strong reproductive barriers can mediate the coexistence of different cytotypes in sympatry, positive frequency-dependent mating disadvantage ultimately drives the transition to single-ploidy populations. However, comprehensive estimates of reproductive isolation among cytotypes and across multiple barriers are rare. We quantify the strength of isolation across multiple reproductive stages in a tetraploid-octoploid contact zone to understand the potential for coexistence. METHODS: Assortative mating due to flowering asynchrony, pollinator behaviour, morphological overlap, self-fertilization and gametic competition between tetraploid and octoploid Gladiolus communis in a contact zone in the Western Iberian Peninsula were assessed in natural and experimental populations to quantify reproductive isolation (RI) between cytotypes. KEY RESULTS: Tetraploids and octoploids have a high degree of overlap in flowering time and similar floral morphology, and are visited by generalist insects without cytotype foraging preferences, resulting in weak pre-pollination RI (from 0.00 to 0.21). In contrast, post-pollination isolation resulting from gametic selection was a strong barrier to inter-cytotype mating, with ploidy composition in stigmatic pollen loads determining the levels of RI (from 0.54 to 1.00). Between-cytotype cross-incompatibility was relatively high (RI from 0.54 to 0.63) as was isolation acquired through self-pollination (RI of 0.59 in tetraploids and 0.39 in octoploids). CONCLUSIONS: Total RI was high for both tetraploids (from 0.90 to 1.00) and octoploids (from 0.78 to 0.98). Such high rates of assortative mating will enable cytotype coexistence in mixed-ploidy populations by weakening the impacts of minority cytotype exclusion. This study reveals the key role of gametic selection in cytotype siring success and highlights the importance of comprehensive estimates across multiple reproductive barriers to understand cytotype interactions at contact zones.


Assuntos
Polinização , Tetraploidia , Humanos , Ploidias , Poliploidia , Isolamento Reprodutivo , Simpatria
8.
Am Nat ; 195(6): E150-E167, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32469663

RESUMO

Partial prezygotic isolation is often viewed as more important than partial postzygotic isolation (low fitness of hybrids) early in the process of speciation. I simulate secondary contact between two populations (species) to examine effects of assortative mating and low hybrid fitness in preventing blending. A small reduction in hybrid fitness (e.g., by 10%) produces a narrower hybrid zone than a strong but imperfect mating preference (e.g., 10 times stronger preference for conspecific over heterospecific mates). In the latter case, rare F1 hybrids find each other attractive (due to assortative mating), leading to the buildup of a continuum of intermediates. The weakness of assortative mating compared with reduced fitness of hybrids in preventing blending is robust to varying genetic bases of these traits. Assortative mating is most powerful in limiting blending when it is encoded by a single locus or is essentially complete, or when there is a large mate search cost. In these cases assortative mating is likely to cause hybrids to have low fitness, due to frequency-dependent mating disadvantage of individuals of rare mating types. These results prompt a questioning of the concept of partial prezygotic isolation, since it is not very isolating unless there is also postzygotic isolation.


Assuntos
Quimera/genética , Especiação Genética , Preferência de Acasalamento Animal , Animais , Simulação por Computador , Feminino , Fluxo Gênico , Aptidão Genética , Masculino , Isolamento Reprodutivo
9.
PLoS One ; 15(5): e0233095, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32433707

RESUMO

Although polyploidy is pervasive and its evolutionary significance has been recognized, it remains unclear how newly formed polyploid species become established. In particular, the impact of multiple origins on genetic differentiation among populations of a polyploid species and whether lineages of independent origins have different evolutionary potentials remain open questions. We used population genetic and phylogenetic approaches to identify genetic differentiation between lineages with independent origins within an allotetraploid fern, Lepisorus nigripes. A total of 352 individuals from 51 populations were collected throughout the distribution range. To examine the genetic structure, multilocus genotyping, Bayesian population structure analysis, and neighbor-net analysis were carried out using single-copy nuclear genes. Phylogenetic trees were constructed to detect recurrent polyploid origins. Proportions of abortive spores were analysed as the measure of postzygotic reproductive isolation. Two genetically distinct lineages, the East-type and the West-type, were distributed mainly in the eastern and western parts, respectively, of the Japanese archipelago. Phylogenetic analyses indicated independent origins of these types and detected additional independent origins within each type. We also revealed limited genetic recombination between both types, even in their sympatric regions. F1 hybrids between the East- and West-types showed a reduction in fertility. It is likely that the East- and West-types formed independently in the eastern and western parts of Japan, respectively. The limited genetic recombination and reduced fertility of hybrids suggest that the two types are at an incipient stage of speciation. Two polyploid lineages with independent geographic origins could develop reproductive isolation barrier(s).


Assuntos
Polypodiaceae/genética , Polypodiaceae/fisiologia , Teorema de Bayes , Evolução Molecular , Filogenia , Poliploidia , Polypodiaceae/classificação , Reprodução/genética , Reprodução/fisiologia , Isolamento Reprodutivo
10.
Sci Rep ; 10(1): 8126, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32415216

RESUMO

Differential visitation of pollinators due to divergent floral traits can lead to reproductive isolation via assortative pollen flow, which may ultimately be a driving force in plant speciation, particularly in areas of overlap. We evaluate the effects of pollinator behavioral responses to variation of intraspecific floral color and nectar rewards, on reproductive isolation between two hybrid flower color morphs (fuchsia and blue) and their parental species Penstemon roseus and P. gentianoides with a mixed-pollination system. We show that pollinators (bumblebees and hummingbirds) exhibit different behavioral responses to fuchsia and blue morphs, which could result from differential attraction or deterrence. In addition to differences in color (spectral reflectance), we found that plants with fuchsia flowers produced more and larger flowers, produced more nectar and were more visited by pollinators than those with blue flowers. These differences influenced the foraging behavior and effectiveness as pollinators of both bumblebees and hummingbirds, which contributed to reproductive isolation between the two hybrid flower color morphs and parental species. This study demonstrates how differentiation of pollination traits promotes the formation of hybrid zones leading to pollinator shifts and reproductive isolation. While phenotypic traits of fuchsia and red flowers might encourage more efficient hummingbird pollination in a mixed-pollination system, the costs of bumblebee pollination on plant reproduction could be the drivers for the repeated shifts from bumblebee- to hummingbird-mediated pollination.


Assuntos
Abelhas/fisiologia , Flores/fisiologia , Penstemon/classificação , Penstemon/fisiologia , Polinização , Isolamento Reprodutivo , Simpatria/fisiologia , Animais , Abelhas/anatomia & histologia , Evolução Biológica , Cor , Penstemon/anatomia & histologia , Fenótipo , Pólen
11.
Am J Bot ; 107(5): 833-841, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32329070

RESUMO

PREMISE: Although polyploidy has been studied since the early 1900s, fundamental aspects of polyploid ecology and evolution remain unexplored. In particular, surprisingly little is known about how newly formed polyploids (neopolyploids) become demographically established. Models predict that most polyploids should go extinct within the first few generations as a result of reproductive disadvantages associated with being the minority in a primarily diploid population (i.e., the minority cytotype principle), yet polyploidy is extremely common. Therefore, a key goal in the study of polyploidy is to determine the mechanisms that promote polyploid establishment in nature. Because premating isolation is critical in order for neopolylpoids to avoid minority cytotype exclusion and thus facilitate establishment, we examined floral morphology and three common premating barriers to determine their importance in generating reproductive isolation of neopolyploids from diploids. METHODS: We induced neopolyploidy in Trifolium pratense and compared their floral traits to the diploid progenitors. In addition to shifts in floral morphology, we examined three premating barriers: isolation by self-fertilization, flowering-time asynchrony, and pollinator-mediated isolation. RESULTS: We found significant differences in the morphology of diploid and neopolyploid flowers, but these changes did not facilitate premating barriers that would generate reproductive isolation of neopolyploids from diploids. There was no difference in flowering phenology, pollinator visitation, or selfing between the cytotypes. CONCLUSIONS: Our results indicate that barriers other than the ones tested in this study-such as geographic isolation, vegetative reproduction, and pistil-stigma incompatibilities-may be more important in facilitating isolation and establishment of neopolyploid T. pratense.


Assuntos
Isolamento Reprodutivo , Trifolium , Flores , Duplicação Gênica , Humanos , Polinização , Poliploidia
12.
Proc Biol Sci ; 287(1924): 20200270, 2020 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-32259470

RESUMO

One hallmark of the East African cichlid radiations is the rapid evolution of reproductive isolation that is robust to full sympatry of many closely related species. Theory predicts that species persistence and speciation in sympatry with gene flow are facilitated if loci of large effect or physical linkage (or pleiotropy) underlie traits involved in reproductive isolation. Here, we investigate the genetic architecture of a key trait involved in behavioural isolation, male nuptial coloration, by crossing two sister species pairs of Lake Victoria cichlids of the genus Pundamilia and mapping nuptial coloration in the F2 hybrids. One is a young sympatric species pair, representative of an axis of colour motif differentiation, red-dorsum versus blue, that is highly recurrent in closely related sympatric species. The other is a species pair representative of colour motifs, red-chest versus blue, that are common in allopatric but uncommon in sympatric closely related species. We find significant quantitative trait loci (QTLs) with moderate to large effects (some overlapping) for red and yellow in the sympatric red-dorsum × blue cross, whereas we find no significant QTLs in the non-sympatric red-chest × blue cross. These findings are consistent with theory predicting that large effect loci or linkage/pleiotropy underlying mating trait differentiation could facilitate speciation and species persistence with gene flow in sympatry.


Assuntos
Ciclídeos/fisiologia , África , Animais , Ciclídeos/genética , Fluxo Gênico , Lagos , Locos de Características Quantitativas , Reprodução , Isolamento Reprodutivo , Simpatria
13.
Curr Biol ; 30(7): R309-R311, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32259503

RESUMO

Identifying the isolating barriers that lead to species formation is challenging. New genomic, phylogenetic and life-history data in Tyrant flycatchers - the largest bird family - suggest long-distance migration contributes to reproductive isolation among closely related forms and to differential diversification across the family.


Assuntos
Passeriformes , Aves Canoras , Migração Animal , Animais , Filogenia , Isolamento Reprodutivo , Aves Canoras/genética
14.
Mutat Res ; 852: 503164, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32265042

RESUMO

In central Brazil, in the municipality of Faina (state of Goiás), the small and isolated village of Araras comprises a genetic cluster of xeroderma pigmentosum (XP) patients. The high level of consanguinity and the geographical isolation gave rise to a high frequency of XP patients. Recently, two founder events were identified affecting that community, with two independent mutations at the POLH gene, c.764 + 1 G > A (intron 6) and c.907 C > T; p.Arg303* (exon 8). These deleterious mutations lead to the xeroderma pigmentosum variant syndrome (XP-V). Previous reports identified both mutations in other countries: the intron 6 mutation in six patients (four families) from Northern Spain (Basque Country and Cantabria) and the exon 8 mutation in two patients from different families in Europe, one of them from Kosovo. In order to investigate the ancestry of the XP patients and the age for these mutations at Araras, we generated genotyping information for 22 XP-V patients from Brazil (16), Spain (6) and Kosovo (1). The local genomic ancestry and the shared haplotype segments among the patients showed that the intron 6 mutation at Araras is associated with an Iberian genetic legacy. All patients from Goiás, homozygotes for intron 6 mutation, share with the Spanish patients identical-by-descent (IBD) genomic segments comprising the mutation. The entrance date for the Iberian haplotype at the village was calculated to be approximately 200 years old. This result is in agreement with the historical arrival of Iberian individuals at the Goiás state (BR). Patients from Goiás and the three families from Spain share 1.8 cM (family 14), 1.7 cM (family 15), and a more significant segment of 4.7 cM within family 13. On the other hand, the patients carrying the exon 8 mutation do not share any specific genetic segment, indicating an old genetic distance between them or even no common ancestry.


Assuntos
DNA Polimerase Dirigida por DNA/genética , Haplótipos , Padrões de Herança , Mutação , Isolamento Reprodutivo , Xeroderma Pigmentoso/genética , Brasil/epidemiologia , Consanguinidade , Europa (Continente)/epidemiologia , Éxons , Feminino , Genética Populacional , Heterozigoto , Homozigoto , Migração Humana , Humanos , Íntrons , Masculino , Fenótipo , Xeroderma Pigmentoso/epidemiologia , Xeroderma Pigmentoso/patologia
16.
Sci Rep ; 10(1): 5116, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198397

RESUMO

Acoustic communication in the form of courtship and mating songs are often involved in reproductive isolation between species of Diptera, such as Drosophila, mosquitoes and sand flies. The patterns of courtship songs in New World sand fly species evolve quickly under sexual selection; and therefore, represent an important trait that can be used as a marker to study the evolution of species complexes and may aid identification of sibling species with a complex. The ability to identify vector species within species complexes is of critical importance for effective and efficient vector control programs. Species-specific song patterns seems to contribute to reproductive isolation in New World sand fly species, suggesting that auditory communication signals may be widespread among these important vectors of leishmaniasis. The main goal of the present study was to characterize the copulatory courtship song of Phlebotomus argentipes, an important vector of visceral leishmaniasis in the Old World. Ph. argentipes males produce acoustic signals during copulation and two types of songs were observed. The one we called primary song is a 'pulse song' with similar length and amplitude to the previously observed 'P1' pattern recorded in Brazilian populations of Lu. longipalpis s.l. The secondary song has 'sine song' characteristics and is quite different from any song produced by New World species. The discovery of this copulation courtship songs in Ph. argentipes supports the possibility that acoustic communication in sandflies might be more widespread than previously thought, including Old World species. Our results highlight the importance of further research on acoustic communication in the Ph. argentipes species complex and other Old World vectors of leishmaniasis.


Assuntos
Corte , Phlebotomus/fisiologia , Isolamento Reprodutivo , Comportamento Sexual Animal/fisiologia , Vocalização Animal/fisiologia , Animais , Drosophila/fisiologia , Feminino , Insetos Vetores/parasitologia , Insetos Vetores/fisiologia , Masculino , Phlebotomus/parasitologia
17.
Proc Natl Acad Sci U S A ; 117(14): 7917-7928, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32193338

RESUMO

A fundamental characteristic of eukaryotic organisms is the generation of genetic variation via sexual reproduction. Conversely, significant large-scale genome structure variations could hamper sexual reproduction, causing reproductive isolation and promoting speciation. The underlying processes behind large-scale genome rearrangements are not well understood and include chromosome translocations involving centromeres. Recent genomic studies in the Cryptococcus species complex revealed that chromosome translocations generated via centromere recombination have reshaped the genomes of different species. In this study, multiple DNA double-strand breaks (DSBs) were generated via the CRISPR/Cas9 system at centromere-specific retrotransposons in the human fungal pathogen Cryptococcus neoformans The resulting DSBs were repaired in a complex manner, leading to the formation of multiple interchromosomal rearrangements and new telomeres, similar to chromothripsis-like events. The newly generated strains harboring chromosome translocations exhibited normal vegetative growth but failed to undergo successful sexual reproduction with the parental wild-type strain. One of these strains failed to produce any spores, while another produced ∼3% viable progeny. The germinated progeny exhibited aneuploidy for multiple chromosomes and showed improved fertility with both parents. All chromosome translocation events were accompanied without any detectable change in gene sequences and thus suggest that chromosomal translocations alone may play an underappreciated role in the onset of reproductive isolation and speciation.


Assuntos
Centrômero/genética , Criptococose/genética , Cryptococcus neoformans/genética , Isolamento Reprodutivo , Sistemas CRISPR-Cas/genética , Instabilidade Cromossômica/genética , Cromossomos/genética , Criptococose/microbiologia , Cryptococcus neoformans/patogenicidade , Quebras de DNA de Cadeia Dupla , Genoma Fúngico/genética , Genômica , Humanos , Translocação Genética/genética
18.
Evolution ; 74(4): 793-794, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32196651

RESUMO

What evolutionary processes shaped the genomic landscape of differentiation in Selasphorus hummingbirds? Battey shows that the islands of differentiation on the Z chromosome are most likely the outcome of linked selection. Furthermore, these islands might contain barrier loci that contribute to reproductive isolation between these hybridizing hummingbirds.


Assuntos
Ilhas Genômicas , Seleção Genética , Animais , Genoma , Isolamento Reprodutivo , Cromossomos Sexuais/genética
19.
Sci Rep ; 10(1): 5502, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32218506

RESUMO

Because it is indicative of reproductive isolation, the amount of genetic introgression across secondary contact zones is increasingly considered in species delimitation. However, patterns of admixture at range margins can be skewed by the regional dynamics of hybrid zones. In this context, we posit an important role for phylogeographic history: hybrid zones located within glacial refugia (putatively formed during the Late-Pleistocene) should be better defined than those located in post-glacial or introduced ranges (putatively formed during the Holocene and the Anthropocene). We test this hypothesis in a speciation continuum of tree frogs from the Western Palearctic (Hyla), featuring ten identified contacts between species spanning Plio-Pleistocene to Miocene divergences. We review the rich phylogeographic literature of this group and examine the overlooked transition between H. arborea and H. molleri in Western France using a multilocus dataset. Our comparative analysis supports a trend that contacts zones resulting from post-glacial expansions and human translocations feature more extensive introgression than those established within refugial areas. Integrating the biogeographic history of incipient species, i.e. their age since first contact together with their genetic divergence, thus appears timely to draw sound evolutionary and taxonomic inferences from patterns of introgression across hybrid zones.


Assuntos
Anuros/classificação , Anuros/genética , Animais , Evolução Molecular , Feminino , França , Introgressão Genética , Especiação Genética , Genética Populacional , História do Século XXI , História Antiga , Humanos , Masculino , Repetições de Microssatélites , Modelos Genéticos , Filogeografia , Refúgio de Vida Selvagem , Isolamento Reprodutivo
20.
Sci Rep ; 10(1): 1502, 2020 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-32001746

RESUMO

Reproductive compatibility usually decreases according to increasing genetic difference and the time of divergence between species. However, the amount of modification required to influence hybridization may vary in different species. Thus, it is extremely important to conduct studies that seek to understand what and how variables influence the reproductive isolation of species. We have explored a system involving two species of subterranean rodents that present morphological, karyotypic, and evolutionary history differences and are capable of generating hybrids. To gain insight into the karyotype organization of genus Ctenomys, we examined the chromosome evolution by classical and molecular cytogenetics of both parental species and hybrids. Furthermore, we have used different approaches to analyze the differences between the parental species and the hybrids, and determined the origin of the hybrids. The results of our work demonstrate unequivocally that some species that present extensive differences in chromosome organization, phenotype, evolutionary history, sperm morphology and genetic, which are usually associated with reproductive isolation, can generate natural hybrids. The results also demonstrate that females of both species are able to generate hybrids with males of the other species. In addition, the chromosome-specific probes prepared from Ctenomys flamarioni provide an invaluable tool for comparative cytogenetics in closely related species.


Assuntos
Roedores/classificação , Roedores/genética , Animais , Coloração Cromossômica , Análise Citogenética , DNA Mitocondrial/genética , Feminino , Especiação Genética , Hibridização Genética , Cariotipagem , Masculino , Repetições de Microssatélites , Filogenia , Isolamento Reprodutivo , Roedores/anatomia & histologia , Crânio/anatomia & histologia , Especificidade da Espécie
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