Taxonomic status of Ceratophysella denticulata (Bagnall, 1941), C. engadinensis (Gisin, 1949) and C. stercoraria Stach, 1963 (Collembola: Hypogastruridae) in the light of laboratory hybridisation studies

2004 ◽  
Vol 35 (3) ◽  
pp. 277-284 ◽  
Author(s):  
Dariusz Skarzynski
Keyword(s):  
Reproductive Isolation ◽  
Taxonomic Status ◽  
Introgressive Hybridisation ◽  
Springtail Species ◽  
Incomplete Reproductive Isolation

AbstractLaboratory hybridisation studies were performed of the springtail species Ceratophysella denticulata, C. engadinensis, C. stercoraria, C. mosquensis, C. impedita and Schaefferia willemi. The studies revealed that the species under consideration are reproductively isolated to different degrees. Rare, unilateral, introgressive hybridisation was detected exclusively between C. denticulata and C. engadinensis. Despite incomplete reproductive isolation these problematic species were recognised as “good” and closely related. The remaining species, including the problematic C. stercoraria, appeared to be completely reproductively isolated and were recognised as “good” and distantly related.

scholarly journals Strong yet incomplete reproductive isolation in Vermivora is not contradicted by other lines of evidence: A reply to Toews et al.

2021 ◽  
Author(s):  
Cody K. Porter ◽  
John L. Confer ◽  
Kyle R. Aldinger ◽  
Ronald A. Canterbury ◽  
Jeffrey L. Larkin ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Incomplete Reproductive Isolation ◽  
Lines Of Evidence

scholarly journals Genome-Wide Regulatory Interactions in the Early Stages of Drosophila Speciation

2020 ◽  
Author(s):  
◽  
Alwyn Clark Go
Keyword(s):  
Reproductive Isolation ◽  
Expression Analysis ◽  
Regulatory Elements ◽  
Specific Expression ◽  
Allele Specific Expression ◽  
Regulatory Interactions ◽  
Early Stages ◽  
Genome Wide ◽  
Allele Specific ◽  
Incomplete Reproductive Isolation

Speciation occurs when reproductive barriers prevent the exchange of genetic information between individuals. A common form of reproductive barrier between species capable of interbreeding is hybrid sterility. Genomic incompatibilities between the divergent genomes of different species contribute to a reduction in hybrid fitness. These incompatibilities continue to accumulate after speciation, therefore, young divergent taxa with incomplete reproductive isolation are important in understating the genetics leading to speciation. Here, I use two Drosophila subspecies pairs. The first is D. willistoni consisting of D. w. willistoni and D. w. winge. The second subspecies pair is D. pseudoobscura, which is composed of D. p. pseudoobscura and D. p. bogotana. Both subspecies pairs are at the early stages of speciation and show incomplete reproductive isolation through unidirectional hybrid male sterility. In this thesis, I performed an exploratory survey of genome-wide expression analysis using RNA-sequencing on D. willistoni and determined the extent of regulatory divergence between the subspecies using allele-specific expression analysis. I found that misexpressed genes showed a degree of tissue specificity and that the sterile male hybrids had a higher proportion of misexpressed genes in the testes relative to the fertile hybrids. The analysis of regulatory divergence between this subspecies pair found a large (66-70%) proportion of genes with conserved regulatory elements. Of the genes showing evidence or regulatory divergence between subspecies, cis-regulatory divergence was more common than other types. In the D. pseudoobscura subspecies pair, I compared sequence and expression divergence and found no support for directional selection driving gene misexpression in their hybrids. Allele-specific expression analysis revealed that compensatory cis-trans mutations partly explained gene misexpression in the hybrids. The remaining hybrid misexpression occurs due to interacting gene networks or possible co-option of cis-regulatory elements by divergent transacting factors. Overall, the results of this thesis highlight the role of regulatory interactions in a hybrid genome and how these interactions could lead to hybrid breakdown by disrupting gene interaction networks.

scholarly journals Incomplete reproductive isolation following host shift in brood parasitic indigobirds

2008 ◽  
Vol 276 (1655) ◽  
pp. 219-228 ◽  
Author(s):  
Christopher N Balakrishnan ◽  
Kristina M Sefc ◽  
Michael D Sorenson
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Host Shift ◽  
Plumage Colour ◽  
Common Ancestry ◽  
Host Races ◽  
Host Shifts ◽  
Molecular Studies ◽  
Close Relatives ◽  
Incomplete Reproductive Isolation

Behavioural and molecular studies suggest that brood parasitic indigobirds ( Vidua spp.) rapidly diversified through a process of speciation by host shift. However, behavioural imprinting on host song, the key mechanism promoting speciation in this system, may also lead to hybridization and gene flow among established indigobird species when and if female indigobirds parasitize hosts already associated with other indigobird species. It is therefore not clear to what extent the low level of genetic differentiation among indigobird species is due to recent common ancestry versus ongoing gene flow. We tested for reproductive isolation among three indigobird species in Cameroon, one of which comprises two morphologically indistinguishable host races. Mimicry of host songs corresponded with plumage colour in 184 male indigobirds, suggesting that females rarely parasitize the host of another indigobird species. Paternity analyses, however, suggest that imperfect specificity in host and/or mate choice allows for continuing gene flow between recently formed host races of the Cameroon Indigobird Vidua camerunensis ; while 63 pairs of close relatives were associated with the same host, two strongly supported father–son pairs included males mimicking the songs of the two different hosts of V. camerunensis . Thus, complete reproductive isolation is not necessarily an automatic consequence of host shifts, a result that suggests an important role for natural and/or sexual selection in indigobird speciation.

Incomplete reproductive isolation betweenRhododendrontaxa enables hybrid formation and persistence

2018 ◽  
Vol 61 (4) ◽  
pp. 433-448 ◽  
Author(s):  
Li‐Jun Yan ◽  
Kevin S. Burgess ◽  
Wei Zheng ◽  
Zhi‐Bin Tao ◽  
De‐Zhu Li ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Hybrid Formation ◽  
Incomplete Reproductive Isolation

scholarly journals Impact of hybridisation in two Cossypha robin-chat species in southern Africa

2019 ◽  
Author(s):  
Jean Mollett ◽  
Naadhirah Munshi ◽  
Craig Symes
Keyword(s):  
Reproductive Isolation ◽  
South African ◽  
Sequence Data ◽  
Taxonomic Status ◽  
Coi Gene ◽  
Genetic Introgression ◽  
Interspecific Hybridisation ◽  
Genetic Clusters ◽  
Reproductive Isolation Mechanisms ◽  
Isolation Mechanisms

Chorister Robin-Chat Cossypha dichroa, a South African forest endemic, and Red-capped Robin-Chat C. natalensis, a widely distributed species in African forest and woodland, are inferred to hybridise in areas of sympatry. DNA was extracted from blood samples of C. dichroa (n = 18), C. natalensis (n = 47), and two phenotypic hybrids. The mitochondrial cytochrome c oxidase I (COI) gene was amplified by PCR and sequenced. Phylogenetic analysis was performed on the sequence data to investigate taxonomic status and putative interspecific hybridisation. Phenotypic hybrids grouped with C. natalensis, suggesting maternal parentage from that species. Intra- and interspecific genetic and geographic distances were compared between C. dichroa and C. natalensis to assess genetic introgression. Seven of the thirteen microsatellite primer pairs developed for C. natalensis cross amplified in C. dichroa. These seven markers were then used for further analysis. STRUCTURE v2.3.4 was used to assign individuals to a particular genetic cluster and determine any admixture. NEWHYBRIDS v1.1 was used to assign hybrid status to samples beyond the F1 generation. Despite the hybridisation events recorded between C. dichroa and C. natalensis they still form two separate clusters as expected, and two genetic clusters (K=2) were identified using STRUCTURE. These two species are proficient vocal mimics and it is likely that reproductive isolation mechanisms are overcome through vocalisations. Genotypic hybrids are evident in the sampled population and hybridisation and backcrossing across a zone of sympatry is occurring. However, hybridisation is expected to have very little evolutionary influence on the integrity of recently diverged species which retain reproductive isolation across a wide region of sympatry through call distinctness.

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