Genetic Variation across a Contact Zone between Montane and Lowland Forms of the Two-Lined Salamander (Eurycea bislineata) Species Complex: A Test of Species Limits

Copeia ◽  
2001 ◽  
Vol 2001 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Kenneth H. Kozak ◽  
Richard R. Montanucci
Keyword(s):  
Genetic Variation ◽  
Contact Zone ◽  
Species Complex ◽  
Species Limits ◽  
Eurycea Bislineata

Patterns of morphological and genetic variation in western Indian Ocean members of the Chaerephon 'pumilus' complex (Chiroptera: Molossidae), with the description of a new species from Madagascar

Zootaxa ◽  
2010 ◽  
Vol 2551 (1) ◽  
pp. 1 ◽  
Author(s):  
STEVEN M. GOODMAN ◽  
WAHEEDA BUCCAS ◽  
THESHNIE NAIDOO ◽  
FANJA RATRIMOMANARIVO ◽  
PETER J. TAYLOR ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Indian Ocean ◽  
Species Complex ◽  
Arabian Peninsula ◽  
Molecular Genetic ◽  
Western Indian Ocean ◽  
D Loop ◽  
Indian Ocean Island ◽  
The Individual ◽  
A New Species

The species delimitations of African, Arabian Peninsula, and western Indian Ocean island members of the Molossidae bat species complex Chaerephon pumilus remain largely unresolved. Based on genetic analyses this group is paraphyletic, with C. leucogaster nested within C. pumilus sensu lato, and the latter is composed of several distinct clades. DNA was isolated from a specimen of C. p. pumilus obtained at the type locality (Massawa, Eritrea). Although incomplete, this sequence allowed us to clearly define which clade is referable to nominate pumilus, a critical step in resolving the systematics of this species complex. Using morphological and molecular genetic (cytochrome b and D-loop sequences) characters, we establish that C. leucogaster and C. 'pumilus' on Madagascar represent two different lineages and that the Malagasy population referred to C. 'pumilus' is specifically distinct from those on Africa, the islands and mainland Africa. The population of C. pusillus from the western Seychelles atoll of Aldabra cluster with that of the Comoros, rather than Madagascar. For numerous other species of volant vertebrates (bats and birds), the origin of the Aldabra fauna is mixed between the Comoros and Madagascar (e.g., Goodman & Ranivo 2008; O'Brien et al. 2009; Pasquet et al. 2007; Warren et al. 2003). Hence, in the case of these 9-17 g Chaerephon bats, these water barriers have been associated with the isolation and subsequent differentiation of populations after successful dispersal and colonization events. In contrast, within the Comoros, there is no apparent genetic structure between with the individual islands, which are separated by 40 and 80 km, indicating that this distance is regularly traversed by these bats and giving rise to intra-archipelago panmixia of populations.

An electrophoretic comparison of Schistosoma japonicum (Trematoda) from different provinces in the People's Republic of China suggests the existence of cryptic species

Parasitology ◽  
1999 ◽  
Vol 119 (4) ◽  
pp. 375-383 ◽  
Author(s):  
N. B. CHILTON ◽  
Q. BAO-ZHEN ◽  
H. O. BØGH ◽  
P. NANSEN
Keyword(s):  
Genetic Variation ◽  
Schistosoma Japonicum ◽  
Species Complex ◽  
Mainland China ◽  
Single Species ◽  
People’S Republic Of China ◽  
People's Republic Of China ◽  
Electrophoretic Study ◽  
Republic Of China ◽  
Animal Hosts

Schistosoma japonicum from the People's Republic of China is considered to represent a single species comprising either 1 or 4 ‘strains’. We conducted an allozyme electrophoretic study to examine the extent of genetic variation in S. japonicum from mainland China. The allelic profiles of S. japonicum from 7 provinces were established at 16 enzyme loci. S. japonicum from Sichuan had 3–5 (19–31%) fixed differences compared with those from Zhejiang, Anhui, Jiangxi, Hunan, Hubei and Yunnan, suggesting that S. japonicum in mainland China represents a species complex. In addition, genetic markers were also established for different laboratory-maintained populations of S. japonicum which has significant implications for studying the biology of these organisms in human and animal hosts, and for the control and surveillance of human schistosomiasis in China.

scholarly journals Incomplete lineage sorting and ancient admixture, and speciation without morphological change in ghost-worm cryptic species

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10896
Author(s):  
José Cerca ◽  
Angel G. Rivera-Colón ◽  
Mafalda S. Ferreira ◽  
Mark Ravinet ◽  
Michael D. Nowak ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Cryptic Species ◽  
Species Complex ◽  
Population Genomics ◽  
Incomplete Lineage Sorting ◽  
Morphological Evolution ◽  
Population Level ◽  
Similar Species ◽  
Lineage Sorting ◽  
Amplification Method

Morphologically similar species, that is cryptic species, may be similar or quasi-similar owing to the deceleration of morphological evolution and stasis. While the factors underlying the deceleration of morphological evolution or stasis in cryptic species remain unknown, decades of research in the field of paleontology on punctuated equilibrium have originated clear hypotheses. Species are expected to remain morphologically identical in scenarios of shared genetic variation, such as hybridization and incomplete lineage sorting, or in scenarios where bottlenecks reduce genetic variation and constrain the evolution of morphology. Here, focusing on three morphologically similar Stygocapitella species, we employ a whole-genome amplification method (WGA) coupled with double-digestion restriction-site associated DNA sequencing (ddRAD) to reconstruct the evolutionary history of the species complex. We explore population structure, use population-level statistics to determine the degree of connectivity between populations and species, and determine the most likely demographic scenarios which generally reject for recent hybridization. We find that the combination of WGA and ddRAD allowed us to obtain genomic-level data from microscopic eukaryotes (∼1 millimetre) opening up opportunities for those working with population genomics and phylogenomics in such taxa. The three species share genetic variance, likely from incomplete lineage sorting and ancient admixture. We speculate that the degree of shared variation might underlie morphological similarity in the Atlantic species complex.

scholarly journals Genetic variation in Plethodon cinereus and Plethodon hubrichti from in and around a contact zone

2020 ◽  
Vol 10 (18) ◽  
pp. 9948-9967
Author(s):  
Robert B. Page ◽  
Claire Conarroe ◽  
Diana Quintanilla ◽  
Andriea Palomo ◽  
Joshua Solis ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Contact Zone ◽  
Plethodon Cinereus

Molecular and morphological variation in the Senna artemisioides complex

2000 ◽  
Vol 48 (5) ◽  
pp. 569 ◽  
Author(s):  
J. E. Holman ◽  
J. Playford
Keyword(s):  
Genetic Variation ◽  
National Park ◽  
Species Complex ◽  
Genetic Distances ◽  
Genetic Differences ◽  
A Value ◽  
Discontinuous Variation ◽  
Integrative Study ◽  
Systematic Relationships ◽  
Foliar Morphology

The Senna artemisioides species complex is characterised by extremely variable foliar morphology. This paper presents the results of an integrative study on reproductive biology, morphology and genetic variation to explore the evolutionary and systematic relationships within this species complex at Idalia National Park in central Queensland. Senna artemisioides showed discontinuous variation at both genetic and phenotypic level. At three sites, foliar morphology was discontinuous, being represented as discrete clusters. Analysis of isozyme variation indicated that many of the discrete morphological groups are distinguished by fixed genetic differences. Morphotypes were also characterised by widespread monomorphism. Most of the genetic variation was between morphotypes rather than within morphotypes. These fixed genetic differences indicate a lack of gene flow between morphotypes and therefore an absence of hybridisation. The two most distinct morphological groups (pyllodinous, pinnate) had high genetic distances of 0.5, a value beyond the usual distance between congeneric species. Forty-two percent of pairwise comparisons between other morphotypes yielded genetic distance values that were relatively high (0.21–0.42). Some phenotypically distinct morphotypes, however, showed little or no isozyme divergence. The combined evidence suggests that genetically distinct morphotypes are independent lineages originating from an ancestral sexual reproductive event that is perpetuated by apomictic reproduction.

Genetic and morphological differentiation among populations of the Rivoli’s Hummingbird (Eugenes fulgens) species complex (Aves: Trochilidae)

The Auk ◽  
2020 ◽  
Vol 137 (4) ◽  
Author(s):  
Luz E Zamudio-Beltrán ◽  
Juan Francisco Ornelas ◽  
Andreia Malpica ◽  
Blanca E Hernández-Baños
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Species Complex ◽  
Ecological Niche Modeling ◽  
Demographic History ◽  
Morphological Differentiation ◽  
Last Interglacial ◽  
Haplotype Networks ◽  
Isthmus Of Tehuantepec

Abstract Genetic variation and phylogeographic studies have been crucial for understanding mechanisms of speciation. We analyzed genetic variation and phylogeography to reconstruct the demographic history of the Rivoli’s Hummingbird (Eugenes fulgens) species complex and also evaluated their morphological differentiation. This widely distributed species inhabits the highlands of Mexico and northern Central America, with 2 subspecies separated by the Isthmus of Tehuantepec (west: E. f. fulgens, east: E. f. viridiceps). We surveyed genetic variation in 2 mitochondrial DNA markers (mtDNA, with 129 individuals) and nuclear DNA (6 microsatellites, with 85 individuals). We also inferred the demographic history, estimated divergence times, and analyzed morphological variation using 470 vouchered specimens. We modeled the current potential distribution of the species using ecological niche modeling and projected it into the past to model the effects of the Pleistocene climatic cycles. Haplotype networks, pairwise FST comparisons, AMOVA, and morphological analysis revealed differences between geographically isolated populations separated by the Isthmus of Tehuantepec (IT; corresponding to the 2 recognized subspecies: fulgens and viridiceps), and by the Motagua-Polochic-Jocotán (MPJ) system fault. Demographic scenarios revealed a contraction in distribution during the last interglacial, and expansion during the Last Glacial Maximum (LGM) with little change since the LGM. Divergence between groups separated by the Isthmus of Tehuantepec ~59,600 yr ago occurred in the presence of gene flow, suggesting that the Isthmus of Tehuantepec is a semipermeable barrier to gene flow. STRUCTURE analyses of microsatellite data detected 3 genetically differentiated groups. Several results fit a model of recent lineage divergence, including a significant signal of genetic differentiation, demographic expansion, decreased gene flow from past to present, and northward expansion during the LGM and contraction during the interglacial periods. We conclude that the genetic differentiation of E. fulgens in the Madrean Pine-Oak Woodlands resulted from recent geographical isolation of populations separated by natural barriers (IT and MPJ).

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