Conservation Genetics of Corroboree Frogs, Pseudophryne-Corroboree Moore (Anura, Myobatrachidae) - Population Subdivision and Genetic-Divergence

1991 ◽  
Vol 39 (3) ◽  
pp. 285 ◽  
Author(s):  
WS Osborne ◽  
JA Norman
Keyword(s):  
Genetic Divergence ◽  
Conservation Management ◽  
Geographic Distance ◽  
Genetic Distances ◽  
Population Subdivision ◽  
Southern Form ◽  
Eastern Australia ◽  
Geographic Populations ◽  
Taxonomic Implications ◽  
Growth Abnormalities

Reproductive compatibility and population genetic structure were examined in the corroboree frog, Pseudophryne corroboree, a species restricted to montane and subalpine environments in south-eastern Australia. The species comprises three geographic populations, represented by two morphological forms. Hybridisation experiments showed that the allopatric populations are interfertile, although crosses between the Snowy Mountains population (southern form) and each of the two northern populations (northern form) resulted in a significantly higher number of tadpoles with growth abnormalities. An electrophoretic examination of metamorphlings indicated that there was considerable genetic divergence between the two forms, with several loci approaching fixation of alternate alleles. The Snowy Mountains population also had substantially reduced levels of genetic variation compared to the two northern populations. Although genetic distances generally correlate with geographic distance, the genetic differences between the northern and southern populations form a pronounced step, not explicable by geographic distance alone. These findings have taxonomic implications which should be taken into account when considering the conservation management of this uncommon species.

Connectivity among populations of pygmy whitefish (Prosopium coulterii) in northwestern North America inferred from microsatellite DNA analyses

2011 ◽  
Vol 89 (4) ◽  
pp. 255-266 ◽  
Author(s):  
E.B. Taylor ◽  
J.L. Gow ◽  
J. Witt ◽  
R. Zemlak
Keyword(s):  
Microsatellite Dna ◽  
Geographic Distance ◽  
Genetic Distances ◽  
Population Subdivision ◽  
Effective Management ◽  
Branch Points ◽  
Stream Networks ◽  
Dna Variation ◽  
Reservoir Watershed ◽  
Northwestern North America

We studied microsatellite DNA variation in 15 populations of northwestern North American pygmy whitefish ( Prosopium coulterii (Eigenmann and Eigenmann, 1892)), an enigmatic freshwater fish thought to be highly fragmented by residency in deep, cold postglacial lakes. Population subdivision (θ) across 10 loci was 0.12 (P < 0.001) across samples, but one western Alaskan population was more divergent than all others (θ = 0.31–0.41, P < 0.001). Within the Williston Reservoir watershed (WRW), θ averaged 0.08 (P < 0.001) and was positively associated with both the geographic distance between localities (r2 = 0.36, P < 0.001) and the number of branch points interconnecting them (r2 = 0.33, P < 0.001). Differentiation among populations was modeled as the sum of the genetic distances for the stream sections interconnecting them (r2 = 0.74). Differences among subwatersheds with the WRW accounted for 5.1% of the total variation in allele frequencies (P < 0.001). Assignment tests suggested limited movement among lakes, with most inferred dispersal between adjacent watersheds. Coalescent analysis strongly supported a gene flow–drift equilibrium model of population structure over a drift-only model. Effective management of diversity in pygmy whitefish requires the maintenance of stream networks that interconnect lakes within a watershed.

scholarly journals Null expectation of spatial correlograms under a stochastic process of genetic divergence with small sample sizes

2000 ◽  
Vol 23 (4) ◽  
pp. 739-743 ◽  
Author(s):  
Mariana Pires de Campos Telles ◽  
José Alexandre Felizola Diniz-Filho
Keyword(s):  
Stochastic Process ◽  
Genetic Divergence ◽  
Isolation By Distance ◽  
Genetic Distances ◽  
Small Sample ◽  
Group Method ◽  
Gene Frequencies ◽  
Exponential Relationship ◽  
Local Populations ◽  
Pair Group

An Ornstein-Uhlenbeck process was used to simulate the exponential relationship between genetic divergence and geographic distances, as predicted by stochastic processes of population differentiation, such as isolation-by-distance, stepping-stone or coalescence models. These simulations were based only on the spatial coordinates of the local populations that defined a spatial unweighted pair-group method using arithmetic averages (UPGMA) link among them. The simulated gene frequency surfaces were then analyzed using spatial autocorrelation procedures and Nei's genetic distances, constructed with different numbers of variables (gene frequencies). Stochastic divergence in space produced strong spatial patterns at univariate and mutivariate levels. Using a relatively small number of local populations, the correlogram profiles varied considerably, with Manhattan distances greater than those defined by other simulation studies. This method allows one to establish a range of correlogram profiles under the same stochastic process of spatial divergence, thereby avoiding the use of unnecessary explanations of genetic divergence based on other microevolutionary processes.

Detection of genetic diversity in rough fescue (Festuca campestris Rydb) populations of southern Alberta and British Columbia, Canada, using RAPD markers

2008 ◽  
Vol 88 (2) ◽  
pp. 307-312
Author(s):  
Zhao Mengli ◽  
Han Bing ◽  
Walter D Willms
Keyword(s):  
Genetic Diversity ◽  
British Columbia ◽  
Genetic Distance ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Distance ◽  
Genetic Distances ◽  
Gene Frequencies ◽  
Southern Alberta ◽  
Potential Adaptation ◽  
Rough Fescue

Mountain rough fescue (Festuca campestris Rydb.) is a tufted native grass in southern Alberta and British Columbia, Canada, and has attracted interest for use in reclamation. However, its seed is often available from only a few localized sources and may not be adapted for areas removed from the collection site. We conducted a study to determine the genetic variability among rough fescue populations to assess its potential adaptation. Thirty plants were collected from each of six populations and analyzed using Random Amplified Polymorphic DNA (RAPD). One population (Kamloops, BC) was separated by several mountain ranges from the five easterly Alberta populations.The Kamloops population was also separated from the Alberta populations by genetic distance in two clusters. Of the total genetic variation present in the data, 21% was found among populations while the remaining (79%) was found within populations. Nei’s genetic distances among populations were related to their geographical distances. Genetic differences among populations appeared to be caused primarily by differences in gene frequencies rather than rare genes. Also, genetic diversity appeared to increase from west to east suggesting that the more easterly populations had greater adaptation potential. We speculate that the more easterly populations are less likely to share genes since the prevailing winds are from the west. Germplasm from the more easterly populations may be used with suitable precautions within Alberta and possibly around Kamloops. Key words: Genetic distance, geographic distance, reclamation, potential adaptation

scholarly journals Genetic divergence in mitochondrial DNA of Anopheles nuneztovari (Diptera: Culicidae) from Brazil and Colombia

2000 ◽  
Vol 23 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Vera Margarete Scarpassa ◽  
Silvia Geurgas ◽  
Ana Maria L. Azeredo-Espin ◽  
Wanderli Pedro Tadei
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Divergence ◽  
Nucleotide Diversity ◽  
Haplotype Diversity ◽  
Sequence Divergence ◽  
Brazilian Amazon ◽  
Restriction Endonucleases ◽  
Separate Species ◽  
Geographic Populations

In the present study, we have examined the variability in Anopheles nuneztovari mitochondrial DNA of three populations from the Brazilian Amazon and one from western Colombia (Sitronela), using four restriction endonucleases (BclI, ClaI, HindIII, SstI). The haplotype diversity (h) was slightly elevated in all populations (0.5000 to 0.6765), whereas the nucleotide diversity (pi) was lower in the Sitronela population (0.0029) and higher in populations from the Brazilian Amazon (0.0056 to 0.0098). The degree of sequence divergence (delta) estimated within the Brazilian Amazon and that in Sitronela (0.0329 to 0.0371) suggests that these geographic populations of A. nuneztovari may eventually constitute separate species. The low sequence divergence values among the three Brazilian Amazon populations (0.0012 to 0.0031) indicate that these populations are genetically similar. These results are consistent with those recently reported for allozymes of these same populations.

scholarly journals Genetic divergence correlates with the contemporary landscape in populations of Slimy Salamander (Plethodon glutinosus) species complex across the lower Piedmont and Coastal Plain of the southeastern United States

2018 ◽  
Vol 96 (11) ◽  
pp. 1244-1254 ◽  
Author(s):  
Walter H. Smith ◽  
Jessica A. Wooten ◽  
Carlos D. Camp ◽  
Dirk J. Stevenson ◽  
John B. Jensen ◽  
...  
Keyword(s):  
South Carolina ◽  
Genetic Distance ◽  
Principal Components ◽  
Coastal Plain ◽  
Genetic Divergence ◽  
Species Complex ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Plethodon Glutinosus ◽  
Isolation By Environment

A primary goal of landscape genetics is to elucidate factors associated with genetic structure among populations. Among the important patterns identified have been isolation by distance (IBD), isolation by barrier (IBB), and isolation by environment (IBE). We tested hypotheses relating each of these possible patterns to genetic divergence in the Slimy Salamander (Plethodon glutinosus (Green, 1818)) species complex across the lower Piedmont and Coastal Plain of Georgia, USA, and adjacent areas of South Carolina, USA. We sequenced 2148 total bp, including three regions of the mitochondrial genome and a nuclear intron, and related genetic distance to GIS-derived surrogate variables representing possible IBD (geographic distance), IBE (principal components of 19 climate variables, watershed, and normalized difference vegetation index (NDVI)), and IBB (streams of fourth order and higher). Multiple matrix regression with randomization analysis indicated significant relationships between genetic distance and two principal components of climate, as well as NDVI. These results support roles for environment (IBE) in helping to drive genetic divergence in this group of salamanders. The absence of a significant influence of IBD and IBB was surprising. It is possible that the signal effects of geographic distance and barriers on genetic divergence may have been erased by more recent responses to the environment.

On the processes of sympatric speciation in the group of «yellow» wagtails in the Middle Volga region

2021 ◽  
pp. 105-111
Author(s):  
Elena Artemieva
Keyword(s):  
Genetic Divergence ◽  
Sympatric Speciation ◽  
Genetic Distances ◽  
Middle Volga Region ◽  
Intraspecific Hybridization ◽  
Yellow Wagtail ◽  
Leading Role ◽  
European Part Of Russia ◽  
Genetic Mechanisms ◽  
Spatio Temporal

This article discusses the mechanisms of sympatric speciation in the group of species of «yellow» wagtails based on hybridization. Interspecific and intraspecific hybridization can be attributed to the genetic mechanisms of divergence of populations of «yellow» wagtails. The existence of hybridization between the subspecies of the white-eared yellow wagtail M. flava beema and the yellow-fronted wagtail M. lutea leads to the emergence and further accumulation in the population of individuals with a light-colored head to varying degrees, the so-called «gray-headed» individuals. Intraspecific hybridization of subspecies forms of the yellow wagtail M. flava — nominative M. f. flava and white-eared M. f. beema leads to constantly occurring genotypic splits, which support intraspecific polymorphism of populations and provide the basis for further genetic divergence of these subspecies and species. The form of "gray-headed" hybrids is characterized by maximum genetic distances (1306.67–1375.67), which may correspond to the species rank. The modern polytypic complex of M. flava (in the narrow sense, a series of species and subspecies of only M. flava) probably formed in historical time on the basis of fan hybridization between the original forms of M. f. flava and M. lutea. Thus, the factors of genetic differentiation and divergence, along with ecological and geographical isolation, play a leading role in the formation of the spatio-temporal and genetic structure of the genus Motacilla. Currently, there is an active process of genetic divergence and separation of subspecies and species forms of «yellow» wagtails under conditions of wide sympatry within a single polytypic complex based on intraspecific and interspecific hybridization in the European part of Russia.

Geographic dimorphism in the mountain brushtail possum (Trichosurus caninus): the case for a new species

2002 ◽  
Vol 50 (4) ◽  
pp. 369 ◽  
Author(s):  
D. B. Lindenmayer ◽  
J. Dubach ◽  
K. L. Viggers
Keyword(s):  
New Species ◽  
New South ◽  
New South Wales ◽  
Distinct Species ◽  
Genetic Distances ◽  
Brushtail Possum ◽  
Genetic Characteristics ◽  
Simple Index ◽  
South Wales ◽  
Eastern Australia

The morphological and genetic characteristics of the mountain brushtail possum (Trichosurus caninus) are described for animals from a range of locations throughout its known geographic distribution in eastern Australia. Although there is considerable variation among populations, unequivocal morphological and genetic differences exist between northern and southern populations of the species. Specimens from southern populations (from Victoria) have a significantly (P < 0.001) larger ear conch, a significantly (P < 0.001) longer pes, and a significantly (P < 0.001) shorter tail than do specimens from northern populations (from New South Wales and Queensland). Animals can be clearly distinguished using a simple index based on these three morphological measures, which are gathered from live animals. North–south dimorphism is strongly supported by patterns in genetic data that show genetic distances of 2.7–3.0% between the southern and northern populations. The combined outcomes of morphological and genetic analyses suggest the existence of two distinct species. We recommend that the northern form, distributed from central New South Wales north to central Queensland, retain the name Trichosurus caninus; the southern form from Victoria is described here as Trichosurus cunninghami, sp. nov. The common names of these new species should be the 'short-eared possum' and the 'mountain brushtail possum', respectively.

Breeding System, Karyotype and Variation Within and Between Populations of Rutidosis leptorrhynchoides F Muell (Asteraceae, Inuleae)

1991 ◽  
Vol 39 (1) ◽  
pp. 85 ◽  
Author(s):  
P Leeton ◽  
YJ Fripp
Keyword(s):  
Chromosome Number ◽  
Breeding System ◽  
Geographic Distance ◽  
Endangered Plant ◽  
Allozyme Analysis ◽  
Self Incompatibility ◽  
Eastern Australia ◽  
Incompatibility System ◽  
Leaf Dimensions ◽  
Allozyme Loci

The endangered plant species, Rutidosis leptorrhynchoides (button wrinklewort), is now known from only a few populations in each of two regions separated by approximately 500 km in south-eastern Australia. Plants were examined from several populations from each region. No differences in chromosome number or morphology were observed among plants or populations. All counts were diploid, 2n = 26. Viable progeny were obtained following self-pollination and allozyme analysis indicated that these progeny were the result of selfing and not agamospermy. This species is not an obligate outcrosser and does not have a classical pre-zygotic self-incompatibility system. However, outcross pollen may have an advantage over self pollen and this species may thus be preferentially outcrossing. The pollen: ovule ratios (mean 3186 ± 48.5) were consistent with this hypothesis. Allele frequencies at allozyme loci diferred little between populations, with an estimated 97% of the variation within populations. There was no correlation between genetic distance and geographic distance. In contrast, for the leaf dimensions of plants germinated and raised together in a glasshouse there were differences between plants from the two regions. It is recommended that populations from both regions should be conserved.

Morphometric differences between Australian wild rabbit populations

1977 ◽  
Vol 25 (4) ◽  
pp. 721 ◽  
Author(s):  
J Taylor ◽  
L Freedman ◽  
TJ Olivier ◽  
J McCluskey
Keyword(s):  
Geographic Distance ◽  
Blood Protein ◽  
Eye Lens ◽  
Wild Rabbit ◽  
British Isles ◽  
Eastern Australia ◽  
Skull Measurements ◽  
Canonical Variates ◽  
Univariate Statistics ◽  
Generalized Distance

Morphometric distances, based on 20 skull measurements, were determined between eight localized Australian wild rabbit populations and a sample from the British Isles. To minimize the influence of age-associated variation in the Australian series, only animals estimated to be at least 12 months old (based on epiphyseal and dry eye-lens aging techniques) were included. Sexes were pooled after univariate and multivariate testing for sexual dimorphism and eliminating bizygomatic breadth. By means of univariate statistics, Mahalanobis generalized distance and canonical analysis, the various Australian and British Isles samples were shown to differ appreciably, morphometric distance increasing clinally in eastern Australia with geographic distance from the point of introduction (Geelong, Vic.). Based on a plot of first and second canonical variates, differences between three Canberra area samples were comparable in magnitude to those between certain populations separated by much greater geographic distances. These findings are consistent with results of studies of blood protein variations in Australian wild rabbit populations.

Genetic divergence for quality, yield and yield components in Yardlong bean[Vigna unguiculata (L.) Walp. ssp.sesquipedalis Verdc.]

2016 ◽  
Author(s):  
E. Rambabu ◽  
K. Ravinder Reddy ◽  
V. Kamala ◽  
P. Saidaiah ◽  
S. R. Pandravada
Keyword(s):  
Genetic Divergence ◽  
Crop Improvement ◽  
Ascorbic Acid Content ◽  
Genetic Distances ◽  
Yield Attributes ◽  
Relative Contribution ◽  
Improvement Programme ◽  
Yardlong Bean ◽  
Clustering Pattern ◽  
Pod Length

Genetic divergence among 41 commercial Yardlong bean genotypes was investigated to select the parents for hybridization using Mahalanobis D2 statistics. The genotypes fall into seven clusters. Cluster VI had the maximum (12) and cluster VII had the minimum (1) number of genotypes. The intra cluster D2 value ranged from 0.00 (Cluster II, III, VI, VII) to 121.69 (Cluster V). The cluster V had the maximum D2 value (121.692) followed by Cluster IV (77.305) and Cluster I (46.391). The inter cluster D2 values of the seven clusters revealed that highest inter cluster generalized distance (607.945) was between cluster V and cluster VII, while the lowest (15.917) was between cluster II and cluster III. Regarding relative contribution of different traits towards divergence, pod length (48.66%) contributed maximum followed by pod ascorbic acid content (20.00%), pod girth (12.20%) and 100 seed weight (12.20%) among Yardlong bean genotypes. Based on genetic distances and clustering pattern, the most divergent genotypes identified are IC-582859, NSJ-362, IC-582850, IC-582872, IC-582851 and IC-582829 from III, V, and VI clusters could be used as best parents on crop improvement programme to produce desirable segregants for yield and yield attributes in Yardlong bean.

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