scholarly journals Morphometric Variation as an Indicator of Genetic Interactions Between Black-Capped and Carolina Chickadees at a Contact Zone in the Appalachian Mountains

The Auk ◽  
2000 ◽  
Vol 117 (2) ◽  
pp. 427-444 ◽  
Author(s):  
Gene D. Sattler ◽  
Michael J. Braun
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Markers ◽  
Hybrid Zone ◽  
Morphological Variation ◽  
Genetic Data ◽  
Mixed Ancestry ◽  
Morphometric Variation ◽  
Average Gene ◽  
Hybridization And Introgression

AbstractWe studied hybridization and introgression between Black-capped (Poecile atricapillus) and Carolina (P. carolinensis) chickadees along two transects in the Appalachians using four genetic markers and multivariate analysis of morphology. Genetic data revealed that at least 58% of the birds in the center of each transect were of mixed ancestry and that recombinant genotypes predominated among hybrids, demonstrating that hybridization is frequent and that many hybrids are fertile. Genetic clines generally were steep and coincident in position, but introgression was evident well beyond the range interface. Introgression was higher at the one autosomal locus surveyed than in mitochondrial DNA or in two sex-linked markers, suggesting that the hybrid zone is a conduit for gene flow between the two forms at some loci. On a broad scale, morphometric variation was concordant with genetic variation. Clines in morphological variation based on principal components (PC) scores were steep and coincident with genetic clines. Also, a strong correlation within a population between PC scores and an individual's genetic makeup suggested that a large amount of morphological variation was genetically determined. However, morphological analysis indicated that hybrids were uncommon on one transect, whereas genetic data clearly showed that they were common on both. In addition, patterns of morphological variation were equivocal regarding introgression across the hybrid zone. Thus, genetic data provided a complementary and more detailed assessment of hybridization, largely due to the discrete nature of genetic variation. Genetic markers are useful in understanding hybridization and introgression, but diagnostic markers may underestimate average gene flow if selection against hybrids maintains steep clines at diagnostic loci. To gain a clearer picture of the genome-wide effects of hybridization, a much larger number of loci must be assayed, including non-diagnostic ones.

scholarly journals A genomic footprint of a moving hybrid zone in marbled newts

2020 ◽  
Author(s):  
Jan W. Arntzen ◽  
Julia López-Delgado ◽  
Isolde van Riemsdijk ◽  
Ben Wielstra
Keyword(s):  
Gene Flow ◽  
Genetic Markers ◽  
Hybrid Zone ◽  
Genetic Material ◽  
River Estuary ◽  
Species Hybrid ◽  
Interspecific Gene Flow ◽  
The Past ◽  
The North ◽  
Triturus Marmoratus

AbstractWe developed a panel of 44 nuclear genetic markers and applied this to two species of marbled newts in the north (Triturus marmoratus) and the south (T. pygmaeus) of the Iberian Peninsula, to document pattern and process of interspecific gene flow. The northernmost occurrence of T. pygmaeus genetic material was in a T. marmoratus population north of the Vouga river estuary. This suggested the past presence of a hybrid zone, possibly coinciding with a natural river outlet at ca. 1200 A.D. Since 1808, the species contact has moved back south to a by then completed, man-made Vouga channel. We also found evidence for a T. marmoratus genomic footprint in T. pygmaeus from the Serra de Sintra, near Lisbon. In combination with a previously reported southern, relic occurrence of T. marmoratus in between both areas, the data point to the superseding with hybridization of T. marmoratus by T. pygmaeus. We estimate that the species hybrid zone has moved over a distance of ca. 215 km.

An Electrophoretic Investigation of Relationships of Diploid and Tetraploid Species of Australian Desert Frogs Neobatrachus (Anura: Myobatrachidae)

1996 ◽  
Vol 44 (6) ◽  
pp. 639 ◽  
Author(s):  
MJ Mahony ◽  
SC Donnellan ◽  
JD Roberts
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Diploid Species ◽  
Genetic Data ◽  
Species Boundaries ◽  
Tetraploid Species ◽  
Allozyme Electrophoresis ◽  
Diploid Population ◽  
Introgressive Hybridisation ◽  
Well Differentiated

Allozyme electrophoresis of 27 loci was used to characterise genetic variation among 29 populations of six diploid species of the myobatrachid frog genus Neobatrachus. All six species are well differentiated genetically with the percentage of fixed differences between species ranging from 11 to 59%. The genetic data are in agreement with the currently accepted species boundaries. The four tetraploid species were examined for 25 of the 27 loci assayed in the diploid species. In contrast to the diploid species, the tetraploid species shared electromorphs with each other at all the loci examined. The tetraploid species were examined for the presence of electromorphs specific to individual diploid species. The majority of these electromorphs were observed in the tetraploid species. For cases in which the range of a tetraploid species contacts that of a diploid species and the diploid population can be characterised by unique electromorphs, then evidence of current gene flow was found in the direction of the tetraploid populations. The data are compatible with single or multiple discrete or hybrid origins of the tetraploids overlain by gene flow among the tetraploids and between the tetraploids and some and perhaps all of the diploids by means of geographically limited but ongoing episodes of introgressive hybridisation.

Landscape Genetics

2019 ◽  
pp. 377-433 ◽  
Author(s):  
Kimberly A. With
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Structure ◽  
Landscape Genetics ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Genetic Data ◽  
Climatic Changes ◽  
Historical Landscape ◽  
Future Landscape

Landscape genetics explores how the microevolutionary processes of gene flow, genetic drift, and natural selection interact with environmental heterogeneity to shape population genetic structure. This chapter begins with a review of the various types of genetic data used in population and landscape genetics and discusses how these data are used to estimate genetic variation (heterozygosity) and gene flow among populations. From there, the chapter considers how population genetic structure can be assayed, which then segues into an analysis of the landscape correlates of population genetic structure, the identification of movement corridors and barriers to gene flow, and the relative effects of current versus historical landscape factors on population genetic structure. The chapter concludes with an overview of evolutionary landscape genetics, by considering the adaptive potential of populations in response to future landscape and climatic changes.

scholarly journals Markers of Genetic Variation in Blue Gourami (Trichogaster trichopterus) as a Model for Labyrinth Fish

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 228
Author(s):  
Gad Degani ◽  
Isana Veksler-Lublinsky ◽  
Ari Meerson
Keyword(s):  
Growth Hormone ◽  
Genetic Variation ◽  
Genetic Markers ◽  
Basic Research ◽  
Coi Gene ◽  
12S Rrna ◽  
Rrna Gene ◽  
Somatotropic Axis ◽  
Genes Encoding ◽  
Growth And Reproduction

Markers of genetic variation between species are important for both applied and basic research. Here, various genes of the blue gourami (Trichogaster trichopterus, suborder Anabantoidei, a model labyrinth fish), many of them involved in growth and reproduction, are reviewed as markers of genetic variation. The genes encoding the following hormones are described: kisspeptins 1 and 2, gonadotropin-releasing hormones 1, 2, and 3, growth hormone, somatolactin, prolactin, follicle- stimulating hormone and luteinizing hormone, as well as mitochondrial genes encoding cytochrome b and 12S rRNA. Genetic markers in blue gourami, representing the suborder Anabantoidei, differ from those in other bony fishes. The sequence of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene of blue gourami is often used to study the Anabantoidei suborder. Among the genes involved in controlling growth and reproduction, the most suitable genetic markers for distinguishing between species of the Anabantoidei have functions in the hypothalamic–pituitary–somatotropic axis: pituitary adenylate cyclase-activating polypeptide and growth hormone, and the 12S rRNA gene.

Morphological and molecular evidence for hybridization and introgression in a willow (Salix) hybrid zone

2000 ◽  
Vol 9 (1) ◽  
pp. 9-24 ◽  
Author(s):  
T. M. Hardig ◽  
S. J. Brunsfeld ◽  
R. S. Fritz ◽  
M. Morgan ◽  
C. M. Orians
Keyword(s):  
Hybrid Zone ◽  
Molecular Evidence ◽  
Hybridization And Introgression

The Use of Protein Electrophoresis for Determining Species Boundaries in Amphipods

Crustaceana ◽  
1993 ◽  
Vol 65 (2) ◽  
pp. 265-277 ◽  
Author(s):  
Barbara A. Stewart
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Morphological Variation ◽  
Protein Electrophoresis ◽  
Species Boundaries ◽  
Allopatric Populations ◽  
A Value ◽  
Electrophoretic Data

AbstractThe use of protein electrophoretic data for determining species boundaries in amphipods is addressed. Analysis of published literature on genetic differentiation in amphipods showed that pairs of allopatric populations which have genetic identities (I) above a value of 0.85 probably represent intraspecific populations, whereas pairs of populations which have genetic identities below about 0.45 probably represent different species. It was recommended that if I values fall between 0.45 and 0.85, additional factors such as evidence of a lack of gene flow between the populations, and concordant morphological variation should be considered.

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