scholarly journals Morphometric variation in a hybrid zone between the weed, Silene vulgaris, and the endemic, Silene uniflora ssp. petraea (Caryophyllaceae), on the Baltic island of Öland

2000 ◽  
Vol 78 (11) ◽  
pp. 1384-1397 ◽  
Author(s):  
Helena Runyeon-Lager ◽  
Honor C Prentice
Keyword(s):  
Hybrid Zone ◽  
Anthropogenic Disturbance ◽  
Parental Species ◽  
Morphological Characters ◽  
Silene Vulgaris ◽  
Disturbance History ◽  
Morphometric Variation ◽  
Transient Nature ◽  
The Baltic ◽  
Habitat Separation

On the island of Öland the weed, Silene vulgaris (Moench) Garcke, and the endemic, Silene uniflora Roth ssp. petraea, hybridize when brought into contact by anthropogenic disturbance. Variation was studied in transects across a hybrid zone where a linear population of S. vulgaris crossed the native habitat of S. uniflora ssp. petraea. Plants were scored for 20 morphological characters. Although individual characters showed clinal trends between weed and endemic, all plants were assignable to one or other parental species. Only 14% of the 554 scored plants showed intermediacy in one or a few characters, and ordinations showed two separate groups of samples. The low number of intermediates is discussed in terms of character choice, habitat separation, disturbance history, and reproductive ecology. The results of the study are consistent with the earlier observation that the species have remained morphologically distinct on Öland, despite evidence of sparse introgression of allozymes from weed to endemic. Disturbance is necessary not only for the creation of intermediate (hybrid) habitats but also for the establishment of the weedy parent. The transient nature of S. vulgaris populations is likely to be important in limiting introgression into S. uniflora ssp. petraea under the present disturbance regime.Key words: genetic assimilation, hierarchical partitioning of diversity, habitat disturbance, introgression, rare species, clines.

Pollen Transfer by Natural Hybrids and Parental Species in an Ipomopsis Hybrid Zone

Evolution ◽  
1998 ◽  
Vol 52 (6) ◽  
pp. 1602 ◽  
Author(s):  
Diane R. Campbell ◽  
Nickolas M. Waser ◽  
Paul G. Wolf
Keyword(s):  
Hybrid Zone ◽  
Parental Species ◽  
Pollen Transfer ◽  
Natural Hybrids

Morphological and molecular characterization of adult worms of Leucochloridium paradoxum Carus, 1835 and L. perturbatum Pojmańska, 1969 (Digenea: Leucochloridiidae) from the great tit, Parus major L., 1758 and similarity with the sporocyst stages

2013 ◽  
Vol 88 (4) ◽  
pp. 506-510 ◽  
Author(s):  
I. Rząd ◽  
P. Hofsoe ◽  
R. Panicz ◽  
J.K. Nowakowski
Keyword(s):  
Parus Major ◽  
Morphological Characters ◽  
Great Tit ◽  
Molecular Techniques ◽  
Morphological Identification ◽  
The Baltic Sea ◽  
The Baltic ◽  
Morphological And Molecular Characterization ◽  
Sea Coast

AbstractUnlike the sporocyst stages, adult leucochloridiid digeneans are difficult to differentiate. Sporocyst broodsacs can be identified on the basis of their colour and banding pattern, but in the absence of broodsacs and when experimental infection cannot be performed, tentative morphological identification needs to be verified, and molecular techniques offer a tool to do this. In this study, adult leucochloridiid digeneans were collected from the great tit (Parus major) found dead at three localities at or near the Baltic Sea coast (Hel, Bukowo-Kopań and Szczecin) in northern Poland. On the basis of differences in their morphological characters, Hel specimens were tentatively assigned to Leucochloridium perturbatum, Bukowo-Kopań and Szczecin specimens being identified tentatively as L. paradoxum. Subsequent ribosomal DNA sequence analysis confirmed the identification of these leucochloridiid flukes. Nucleotide sequences discriminating between the two species were identical to those used by earlier authors as characteristic of two distinctly different sporocyst broodsacs representing L. perturbatum and L. paradoxum.

scholarly journals Variations in genetic structure and male genitalia suggest recent lineage diversification in the Neotropical dung beetle complex Canthon cyanellus (Scarabaeidae: Scarabaeinae)

2020 ◽  
Vol 131 (3) ◽  
pp. 505-520
Author(s):  
Janet Nolasco-Soto ◽  
Mario E Favila ◽  
Alejandro Espinosa De Los Monteros ◽  
Jorge González-Astorga ◽  
Gonzalo Halffter ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Morphological Variation ◽  
Male Genitalia ◽  
Morphological Variability ◽  
Dung Beetle ◽  
Morphological Characters ◽  
Taxonomic Assignment ◽  
Morphometric Variation ◽  
Evolutionary Forces ◽  
Significant Genetic Structure

Abstract We analysed the genetic divergence and morphology of the aedeagus (i.e. phallobase and parameres) in Canthon cyanellus at different geographical levels. The results from both approaches were compared with the current taxonomic assignment of the C. cyanellus complex, which includes three subspecies. We found a high variation in all the morphological characters of the aedeagus in the populations analysed; the morphometric variation was not geographically structured, either by population or by region. The genealogical analysis indicates a significant genetic structure that does not match either the morphological variation in the male genitalia or the previous subspecific taxonomic classification. Our results suggest that the morphological variation of the aedeagus is seemingly not an isolating reproductive barrier and that the intra- and interpopulation morphological variability of the aedeagus in the C. cyanellus complex does not permit the division into several species. We suggest that other evolutionary forces, such as genetic drift and sexual selection, have influenced the evolution of the male genitalia and the incipient differentiation of this species complex.

scholarly journals Hybridization and hybrid zone stability between two lizards explained by population genetics and niche quantification

2020 ◽  
Vol 190 (2) ◽  
pp. 757-769
Author(s):  
Imanol Cabaña ◽  
Margarita Chiaraviglio ◽  
Valeria Di Cola ◽  
Antoine Guisan ◽  
Olivier Broennimann ◽  
...  
Keyword(s):  
Hybrid Zone ◽  
Parental Species ◽  
Niche Overlap ◽  
Analysis Framework ◽  
Nuclear Marker ◽  
Lizard Species ◽  
New Models ◽  
Species Evolution ◽  
Main Factors ◽  
The Stability

Abstract Understanding the factors that affect hybridization is an important issue in the study of species evolution. In this work, we analyse the genetic structure of two lizard species, Salvator merianae and Salvator rufescens, at a microscale within a climatic niche analysis framework, to reveal the main factors that contribute to the stability of their hybrid zone. We assess the effect of climate in hybridization by quantifying and decomposing the niche overlap of both species. Using a mitochondrial and a nuclear marker, we find that hybridization is frequent and is not restricted to the sympatric region. The gene flow is mainly from S. rufescens to S. merianae, with introgression into the range of S. merianae. Also, S. merianae would have long been present in the area, while S. rufescens appears to be a recent colonizer. The climate contributes to the population structure of S. merianae, but not to that of S. rufescens. The niches occupied by S. rufescens in the hybrid zone and the non-hybrid zone are similar, while the niches of S. merianae are different. Our results do not fit previous models of hybrid zone stability, suggesting the need to develop new models that consider the evolutionary factors that can differentially affect parental species and hybrids.

scholarly journals Influence of Niche Overlap and Territoriality on Hybridization Between Hermit Warblers and Townsend's Warblers

The Auk ◽  
2000 ◽  
Vol 117 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Scott F. Pearson ◽  
David A. Manuwal
Keyword(s):  
Habitat Use ◽  
Hybrid Zone ◽  
Parental Species ◽  
Niche Overlap ◽  
Habitat Characteristics ◽  
Hybrid Zones ◽  
Parental Fitness ◽  
Habitat Transition ◽  
Habitat Variables ◽  
Washington Cascades

Abstract Hybrid zones between Townsend's Warblers (Dendroica townsendi) and Hermit Warblers (D. occidentalis) in the Pacific Northwest are narrow relative to estimated dispersal distances and appear to be moving, with Townsend's replacing Hermits. We examined whether the habitat-transition and parental-fitness asymmetry models can explain why these zones are narrow and moving by comparing habitat variables associated with warbler territories in the Washington Cascades hybrid zone. Habitat variables did not differ among phenotypes, suggesting that the habitat-transition model cannot explain the narrow and dynamic nature of this hybrid zone. Habitat characteristics of Hermit Warbler territories did not differ inside versus outside the hybrid zone, also suggesting that this zone is not associated with a region of habitat transition. The lack of difference in habitat use could be the result of comparing variables that are not important to pairing success. However, warblers tended to select territories on west-southwest aspects. South aspects in the southern Washington Cascades are dominated by Douglas fir (Pseudotsuga menziesii) and true fir, which is a habitat selected by female warblers when choosing among territories and males. The parental-fitness asymmetry model does not necessarily make predictions about habitat use within the hybrid zone but predicts the superiority of one parental species over the other. However, if significant overlap occurs in habitat use or niche (as in these warblers), then competition between parental species is likely to occur. To determine whether these species compete, we mapped 12 warbler territories and monitored an additional 94 territories throughout the breeding season and found that all males with neighbors compete for and hold exclusive territories. Thus, the pattern of habitat use and territoriality is consistent with the parental-fitness asymmetry model.

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.

Morphometric variation in a hybrid zone of two subspecies of Gerris costae (Heteroptera: Gerridae) in the Maritime Alps

1994 ◽  
Vol 7 (6) ◽  
pp. 697-712 ◽  
Author(s):  
Carlo Rodolfo Largiader ◽  
Christian Peter Klingenberg ◽  
Manfred Zimmermann
Keyword(s):  
Hybrid Zone ◽  
Maritime Alps ◽  
Morphometric Variation

scholarly journals Interspecific mitochondrial DNA transfer and the colonization of Scandinavia by mice

1987 ◽  
Vol 49 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Ulf Gyllensten ◽  
Allan C. Wilson
Keyword(s):  
Mitochondrial Dna ◽  
Hybrid Zone ◽  
Restriction Enzymes ◽  
Electrophoretic Analysis ◽  
Nuclear Genes ◽  
Mouse Population ◽  
Apparent Lack ◽  
North Germany ◽  
Founder Event ◽  
The Baltic

SummaryRestriction enzymes were used to search for genetic variability at 162 cleavage sites in mitochondrial DNA (mtDNA) purified from 22 mice caught at seven Swedish localities. Although all of these mice bear the nuclear genes of Mus musculus, they bear the mtDNA of M. domesticus exclusively. Yet, some of the Swedish localities are 750 km away from the hybrid zone between these two species. Furthermore, only one type of mtDNA was found at the seven Swedish localities; this type was found before at an eighth locality in Sweden as well as in Jutland north of the hybrid zone. The apparent lack of mtDNA divergence in the mouse population of Sweden contrasts with the extensive divergence usually found within other geographic areas in Europe, Africa and North America. Electrophoretic analysis of proteins encoded by nuclear genes indicates that the Swedish mice have lower average heterozygosity than Danish and Central European populations of musculus mice. These findings lead us to suggest that the source of the commensal mouse population in Sweden was a small propagule that originated from a population situated only a few kilometres to the east of the point at which the hybrid zone on the European mainland meets the Baltic Sea, namely on East Holstein. Such a founder event may have been associated with the spread of farming from north Germany into Sweden about 4000 years ago.

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