Incipient speciation in Scandinavian Distichium capillaceum (Distichiaceae, Bryophyta)

Field collections of Chironomus oppositus from certain localities in Tasmania, in particular from Bellerive, consistently show distributions of inversions different to those found in the normal form, which is referred to as form A and occurs in mainland Australia and most other Tasmanian populations. These collections showed: (1) a marked deficiency of almost all inversion heterozygotes; (2) significant groups of associated sequences which can be used to define two additional forms, referred to as form B and form C. Since forms B and C have so far only been found together, it would appear that this represents an unusual situation in insect speciation. This karyotypic divergence must be maintained by some restriction on interbreeding, both between these two groups and also between them and form A, with which they appear to coexist in some localities.

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Molecular evidence of incipient speciation within Anopheles gambiae s.s. in West Africa

Insect Molecular Biology ◽

10.1046/j.1365-2583.2001.00235.x ◽

2001 ◽

Vol 10 (1) ◽

pp. 9-18 ◽

Cited By ~ 223

Author(s):

A. della Torre ◽

C. Fanello ◽

M. Akogbeto ◽

J. Dossou-yovo ◽

G. Favia ◽

...

Keyword(s):

West Africa ◽

Anopheles Gambiae ◽

Molecular Evidence ◽

Incipient Speciation ◽

Anopheles Gambiae S.S

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GENETICS OF INCIPIENT SPECIATION INDROSOPHILA MOJAVENSIS:II. HOST PLANTS AND MATING STATUS INFLUENCE CUTICULAR HYDROCARBON QTL EXPRESSION AND G × E INTERACTIONS

Evolution ◽

10.1111/j.1558-5646.2009.00661.x ◽

2009 ◽

Vol 63 (7) ◽

pp. 1712-1730 ◽

Cited By ~ 51

Author(s):

William J. Etges ◽

Cassia Cardoso de Oliveira ◽

Michael G. Ritchie ◽

Mohamed A. F. Noor

Keyword(s):

Host Plants ◽

Cuticular Hydrocarbon ◽

Incipient Speciation ◽

Mating Status

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Cuticular Hydrocarbon Content that Affects Male Mate Preference of Drosophila melanogaster from West Africa

International Journal of Evolutionary Biology ◽

10.1155/2012/278903 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Aya Takahashi ◽

Nao Fujiwara-Tsujii ◽

Ryohei Yamaoka ◽

Masanobu Itoh ◽

Mamiko Ozaki ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Low Frequency ◽

Cuticular Hydrocarbon ◽

Inhibitory Effect ◽

Incipient Speciation ◽

Transfer Experiment ◽

Premating Isolation ◽

Potential Factor ◽

Male Mate ◽

Different Strains

Intraspecific variation in mating signals and preferences can be a potential source of incipient speciation. Variable crossability between Drosophila melanogaster and D. simulans among different strains suggested the abundance of such variations. A particular focus on one combination of D. melanogaster strains, TW1(G23) and Mel6(G59), that showed different crossabilities to D. simulans, revealed that the mating between females from the former and males from the latter occurs at low frequency. The cuticular hydrocarbon transfer experiment indicated that cuticular hydrocarbons of TW1 females have an inhibitory effect on courtship by Mel6 males. A candidate component, a C25 diene, was inferred from the gas chromatography analyses. The intensity of male refusal of TW1 females was variable among different strains of D. melanogaster, which suggested the presence of variation in sensitivity to different chemicals on the cuticle. Such variation could be a potential factor for the establishment of premating isolation under some conditions.

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Behavioral Isolation and Incipient Speciation in Birds

Annual Review of Ecology Evolution and Systematics ◽

10.1146/annurev-ecolsys-110617-062646 ◽

2018 ◽

Vol 49 (1) ◽

pp. 1-24 ◽

Cited By ~ 21

Author(s):

J. Albert C. Uy ◽

Darren E. Irwin ◽

Michael S. Webster

Keyword(s):

Behavioral Changes ◽

Reproductive Barriers ◽

Incipient Speciation ◽

Mating Preferences ◽

Early Stages ◽

Behavioral Isolation ◽

Intermediate Phenotypes ◽

Postzygotic Barriers ◽

Avian Diversification ◽

And Migration

Behavioral changes, such as those involved in mating, foraging, and migration, can generate reproductive barriers between populations. Birds, in particular, are known for their great diversity in these behaviors, and so behavioral isolation is often proposed to be the major driver of speciation. Here, we review empirical evidence to evaluate the importance of behavioral isolation in the early stages of avian speciation. Experimentally measured mating preferences indicate that changes in mating behavior can result in premating barriers, with their strength depending on the extent of divergence in mating signals. Differences in migratory and foraging behavior also can play important roles in generating reproductive barriers in the early stages of speciation. However, because premating behavioral isolation is imperfect, extrinsic postzygotic barriers, in the form of selection against hybrids having intermediate phenotypes, also play an important role in avian diversification, especially in completing the speciation process.

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Population-Based Cytogenetic Banding Analysis and Phylogenetic Relationships of the Neotropical Fungus-Farming Ant Trachymyrmex holmgreni Wheeler, 1925

Cytogenetic and Genome Research ◽

10.1159/000503913 ◽

2019 ◽

Vol 159 (3) ◽

pp. 151-161 ◽

Cited By ~ 4

Author(s):

Ricardo Micolino ◽

Maykon P. Cristiano ◽

Danon C. Cardoso

Keyword(s):

Genetic Variation ◽

Phylogenetic Reconstruction ◽

Population Based ◽

Population Variation ◽

Incipient Speciation ◽

Telomeric Sequences ◽

New Information ◽

Banding Analysis ◽

Pattern Characteristic ◽

Northern Brazil

Trachymyrmex is one of the most species-rich genera within fungus-farming ants and presents intraspecific cytogenetic polymorphisms as well as possible cryptic species. This ant genus is currently paraphyletic. Therefore, to unravel systematic and taxonomic misunderstandings, it is necessary to incorporate new information. We aimed to cytogenetically and genetically examine Trachymyrmex holmgreni populations from southern and northern Brazil to identify intraspecific chromosomal variations that support incipient speciation and reveal the species' position in a molecular phylogeny. Our cytogenetic approach did not show population variation in the mapping of both 18S rDNA and the TTAGG(6) motif, presenting instead a pattern characteristic of correlated species. However, the clustered pattern of the microsatellite GA(15) showed significant differences among populations: a well-defined block in each homologue, distinctly irregular signs between homologues, and blocks in 2 pairs of homologues. Our phylogenetic reconstruction yielded unexpected results, grouping representatives of 3 former morphological groups into 1 clade, namely T. urichii, T. papulatus, and T. holmgreni. Previously, it was suggested that northern and southern populations of T. holmgreni may be undergoing incipient speciation, but we can only indicate that the southernmost population differs prominently from the others in its distribution pattern of the microsatellite GA(15). Our study also supports the uniformity of karyotypes and repetitive DNA from both telomeric sequences and ribosomal DNA in Trachymyrmex studied here. In addition, we clarify some phylogenetic uncertainties within the genus and suggest further relevant systematic changes. Finally, additional studies utilizing other probes and additional populations may allow the detection of hidden genetic variation.

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The Role of Plasticity and Adaptation in the Incipient Speciation of a Fire Salamander Population

Genes ◽

10.3390/genes10110875 ◽

2019 ◽

Vol 10 (11) ◽

pp. 875

Author(s):

Joana Sabino-Pinto ◽

Daniel J. Goedbloed ◽

Eugenia Sanchez ◽

Till Czypionka ◽

Arne W. Nolte ◽

...

Keyword(s):

Gene Expression ◽

Phenotypic Plasticity ◽

Local Adaptation ◽

Habitat Preferences ◽

Genetic Change ◽

Incipient Speciation ◽

Expression Of Genes ◽

Species Specific ◽

Reciprocal Transfer ◽

High Degree

Phenotypic plasticity and local adaptation via genetic change are two major mechanisms of response to dynamic environmental conditions. These mechanisms are not mutually exclusive, since genetic change can establish similar phenotypes to plasticity. This connection between both mechanisms raises the question of how much of the variation observed between species or populations is plastic and how much of it is genetic. In this study, we used a structured population of fire salamanders (Salamandra salamandra), in which two subpopulations differ in terms of physiology, genetics, mate-, and habitat preferences. Our goal was to identify candidate genes for differential habitat adaptation in this system, and to explore the degree of plasticity compared to local adaptation. We therefore performed a reciprocal transfer experiment of stream- and pond-originated salamander larvae and analyzed changes in morphology and transcriptomic profile (using species-specific microarrays). We observed that stream- and pond-originated individuals diverge in morphology and gene expression. For instance, pond-originated larvae have larger gills, likely to cope with oxygen-poor ponds. When transferred to streams, pond-originated larvae showed a high degree of plasticity, resembling the morphology and gene expression of stream-originated larvae (reversion); however the same was not found for stream-originated larvae when transferred to ponds, where the expression of genes related to reduction-oxidation processes was increased, possibly to cope with environmental stress. The lack of symmetrical responses between transplanted animals highlights the fact that the adaptations are not fully plastic and that some level of local adaptation has already occurred in this population. This study illuminates the process by which phenotypic plasticity allows local adaptation to new environments and its potential role in the pathway of incipient speciation.

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