Allozyme variation in sugar maple at the northern limit of its range in Ontario, Canada

1989 ◽  
Vol 19 (4) ◽  
pp. 509-514 ◽  
Author(s):  
D. J. Perry ◽  
P. Knowles
Keyword(s):  
Genetic Variation ◽  
Sugar Maple ◽  
Geographic Distance ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Canonical Discriminant Analysis ◽  
Ancestral Population ◽  
Allelic Heterogeneity ◽  
Northern Limit ◽  
Northern Ontario

Genetic variation in five populations of sugar maple (Acersaccharum Marsh.) from northern Ontario was analysed electrophoretically for seven enzymes encoded by 11 structural loci. On average, populations were polymorphic at 38.2% of the loci, with 1.95 alleles per locus. Although FST estimates indicated that only 3% of the genetic variability was among populations, there was significant allelic heterogeneity at all polymorphic loci. Canonical discriminant analysis also indicated substantial differentiation among populations. Genetic distances between populations ranged from 0.0009 to 0.0125, but no relationship with geographic distance was apparent. It is suggested that pockets of sugar maple found at the northern limit of its range in Ontario may be relics of a more continuous ancestral population which may have existed during the hypsithermal interval.

Patterns of allozyme variation in tamarack (Larix laricina) from northern Ontario

1991 ◽  
Vol 69 (11) ◽  
pp. 2468-2474 ◽  
Author(s):  
Zhaowei Liu ◽  
Peggy Knowles
Keyword(s):  
Function Analysis ◽  
Geographic Location ◽  
Allozyme Variation ◽  
Wide Distribution ◽  
Genetic Distances ◽  
Larix Laricina ◽  
Northern Ontario ◽  
Total Genetic Diversity ◽  
Population Genetic Variation ◽  
Genotypic Structure

Rooted cuttings from approximately 26 trees (range 9–37) from each of 44 populations of tamarack (Larix laricina (Du Roi) K. Koch) in northern Ontario were analyzed electrophoretically for allozyme variation in 13 enzyme systems coded by 18 loci. A low level of variability relative to many other conifers was found, with expected and observed heterozygosity per population of 0.104 and 0.096, respectively, χ2 tests for allelic homogeneity among populations indicated heterogeneity (α = 0.05) at four loci. Approximately 2% of the total genetic diversity occurred among populations, with the remainder (98%) residing within populations. The mean genetic distance over all pairs of tamarack populations was 0.0025. Four methods of cluster analysis based on genetic distances and a discriminant function analysis of the genotypic structure of the populations revealed no consistent patterns of variation relative to geographic location, although one of the clustering procedures showed a weak east–west pattern. The results indicate that (i) the level of variation in these populations of tamarack is substantially less than that previously reported for its range-wide distribution; (ii) the population structure of tamarack is consistent with that of other conifers, indicating little deviation from Hardy–Weinberg expected genotypic frequencies and low levels of differentiation; and (iii) the distribution of the variation provides little evidence to support the model of two routes of tamarack post glacial reinvasion meeting west of Lake Superior. Key words: tamarack, eastern larch, Larix laricina, allozyme, isozyme, population, genetic variation, northern Ontario.

scholarly journals A preliminary study of the allozyme variation in the grey hamster, Cricetulus migratorius (Mammalia: Rodentia), from the Asian part of Turkey

2011 ◽  
Vol 63 (2) ◽  
pp. 381-391 ◽  
Author(s):  
Osman İbiş ◽  
Coşkun Tez ◽  
Servet Özcan ◽  
Metin Kiliç ◽  
Murat Telcioğlu
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Gel Electrophoresis ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Average Value ◽  
Enzyme Systems ◽  
The Mean ◽  
Preliminary Study ◽  
Allozyme Loci

The aim of the present study was to evaluate the degree of genetic variation and divergence by cellulose acetate gel electrophoresis between samples of Cricetulus migratorius, a cricetine rodent distributed in the Asian part (Anatolia) of Turkey. Out of twenty allozyme loci scored for fifteen enzyme systems, eleven loci were detected to be polymorphic in at least one locality of the Turkish C. migratorius. Indices of genetic variability (the percentage of polymorphic loci, mean number of alleles per locus, and mean observed and expected heterozygosities) were found to be P(95%) = 28, A = 1.3, Ho = 0.226 and He = 0.218, respectively. Nei?s unbiased genetic distances ranged from 0.000 to 0.153, with an average value of 0.069. The mean gene flow was calculated to be Nm = 0.7484. This is a preliminary study describing the allozymic variations of C. migratorius from Turkey. As there are no extensive data on the allozymic variations of C. migratorius from other regions, our results could not be compared, in detail with those of other populations of the species C. migratorius.

Isozyme variation and its environmental correlates in Elymus glaucus from the California Floristic Province

2001 ◽  
Vol 79 (2) ◽  
pp. 139-153 ◽  
Author(s):  
Barbara L Wilson ◽  
Jay Kitzmiller ◽  
Wayne Rolle ◽  
Valerie D Hipkins
Keyword(s):  
Genetic Variation ◽  
San Francisco ◽  
Sierra Nevada ◽  
Geographic Distance ◽  
Geographic Location ◽  
Taxonomic Status ◽  
Genetic Distances ◽  
Leaf Pubescence ◽  
Seed Transfer ◽  
Elymus Glaucus

Genetic variation in the self-fertile, allotetraploid grass Elymus glaucus Buckley was assessed using isozymes in 133 populations from southwestern Oregon and from the San Francisco Bay area and central Sierra Nevada mountains in California. Elymus glaucus was highly (98.5%) homozygous but also highly variable; 77% of loci were polymorphic, and the mean number of alleles per locus was 2.96. Populations were highly differentiated, with 40% of variation among populations. Geographic and genetic distances among populations were not correlated, except that populations collected within 5 km were generally more similar than average. Genetic distance among populations could not be predicted from geographic distance, geographic location, foliage pubescence, serpentine substrate, or habitat moisture. However, two genetic clusters, associated with elevation, did emerge. The taxonomic status of Elymus glaucus ssp. jepsonii (Burtt Davy) Gould, based on leaf pubescence, was not supported.Key words: Elymus glaucus, isozyme, genetic variation, Poaceae, polyploid, seed transfer.

scholarly journals Levels of genetic polymorphism: marker loci versus quantitative traits

1998 ◽  
Vol 353 (1366) ◽  
pp. 187-198 ◽  
Author(s):  
R. K. Butlin ◽  
T. Tregenza
Keyword(s):  
Genetic Variation ◽  
Quantitative Traits ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Stabilizing Selection ◽  
Limited Data ◽  
Prezygotic Isolation ◽  
Marker Loci ◽  
Mating Signal

Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to which the pattern observed for allozymes can be used to infer patterns of genetic variation in quantitative traits depends on the forces generating and maintaining variability. Allozyme variation is probably not strictly neutral but, nevertheless, heterozygosity is expected to be influenced by population size and genetic distance will be affected by time since divergence. The same is true for quantitative traits influenced by many genes and under weak stabilizing selection. However, the limited data available suggest that allozyme variability is a poor predictor of genetic variation in quantitative traits within populations. It is a better predictor of general phenotypic divergence and of postzygotic isolation between populations or species, but is only weakly correlated with prezygotic isolation. Studies of grasshopper and planthopper mating signal variation and assortative mating illustrate how these characters evolve independently of general genetic and morphological variation. The role of such traits in prezygotic isolation, and hence speciation, means that they will contribute significantly to the diversity of levels of genetic variation within and among species.

Genetic variation and structure at three spatial scales for Acersaccharum (sugar maple) in Canada and the implications for conservation

1993 ◽  
Vol 23 (12) ◽  
pp. 2568-2578 ◽  
Author(s):  
A.G. Young ◽  
S.I. Warwick ◽  
H.G. Merriam
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Sugar Maple ◽  
Spatial Scales ◽  
Allozyme Variation ◽  
Species Range ◽  
Conservation Strategies ◽  
Single Region ◽  
Selection Gene ◽  
Trees And Shrubs

Genetic (allozyme) variation and genetic structure in Acersaccharum Marsh. (sugar maple) were examined at three spatial scales: among populations across the species' range in Canada, among populations within a single region, and among individuals within populations. Levels of genetic variation were slightly lower than for other North American angiosperm trees and shrubs; however, genetic structure was observed at all three scales. Possible processes associated with the patterns of variation at different scales ranged from post-Pleistocene glacial migration to flowering ecology. Genetic conservation strategies for A. saccharum should aim to maintain a spatial hierarchy of populations and individuals throughout the species' range in Canada. This approach should encompass that genetic variation already in existance, and provide the range of spatial and organizational scales necessary for processes such as selection, gene flow, and genetic drift to continue to operate.

scholarly journals POPULATION GENETICS OF ALLOZYME VARIATION IN NEUROSPORA INTERMEDIA

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 785-805
Author(s):  
P T Spieth
Keyword(s):  
Genetic Variation ◽  
Vegetative Reproduction ◽  
Vascular Plant ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Regular Feature ◽  
Local Populations ◽  
Neurospora Intermedia ◽  
Pattern Of Variation ◽  
High Level

ABSTRACT Electrophoretically detectable variation in the fungus Neurospora intermedia has been surveyed among isolates from natural populations in Malaya, Papua, Australia and Florida. The principal result is a pattern of genetic variation within and between populations that is qualitatively no different than the well documented patterns for Drosophila and humans. In particular, there is a high level of genetic variation, the majority of which occurs at the level of local populations. Evidence is presented which argues that N. intermedia has a population structure analogous to that of an annual vascular plant with a high level of vegetative reproduction. Sexual reproduction appears to be a regular feature in the biology of the species. Substantial heterokaryon function seems unlikely in natural populations of N. intermedia. Theoretical considerations concerning the mechanisms underlying the observed pattern of variation most likely should be consistent with haploid selection theory. The implications of this constraint upon the theory are discussed in detail, leading to the presentation of a model based upon the concept of environmental heterogeneity. The essence of the model, which is equally applicable to haploid and diploid situations, is a shifting distribution of multiple adaptive niches among local populations such that a given population has a small net selective pressure in favor of one allele or another, depending upon its particular distribution of niches. Gene flow among neighboring populations with differing net selective pressures is postulated as the principal factor underlying intrapopulational allozyme variation.

Significant genetic differences among Heterodera schachtii populations within and among sugar beet production areas

Nematology ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 165-177 ◽  
Author(s):  
Rasha Haj Nuaima ◽  
Johannes Roeb ◽  
Johannes Hallmann ◽  
Matthias Daub ◽  
Holger Heuer
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Spatial Scales ◽  
Geographic Distance ◽  
Heterodera Schachtii ◽  
Parasitic Nematodes ◽  
Neutral Genetic Variation ◽  
Production Areas

Summary Characterising the non-neutral genetic variation within and among populations of plant-parasitic nematodes is essential to determine factors shaping the population genetic structure. This study describes the genetic variation of the parasitism gene vap1 within and among geographic populations of the beet cyst nematode Heterodera schachtii. Forty populations of H. schachtii were sampled at four spatial scales: 695 km, 49 km, 3.1 km and 0.24 km. DGGE fingerprinting showed significant differences in vap1 patterns among populations. High similarity of vap1 patterns appeared between geographically close populations, and occasionally among distant populations. Analysis of spatially sampled populations within fields revealed an effect of tillage direction on the vap1 similarity for two of four studied fields. Overall, geographic distance and similarity of vap1 patterns of H. schachtii populations were negatively correlated. In conclusion, the population genetic structure was shaped by the interplay between the genetic adaptation and the passive transport of this nematode.

scholarly journals Genetic Variation Among Colletotrichum graminicola Isolates from Four Hosts Using Isozyme Analysis

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 402-406 ◽  
Author(s):  
B. J. Horvath ◽  
J. M. Vargas
Keyword(s):  
Genetic Variation ◽  
Genetic Distance ◽  
Geographic Origin ◽  
Creeping Bentgrass ◽  
Genetic Distances ◽  
Colletotrichum Graminicola ◽  
Annual Bluegrass ◽  
Close Relationship ◽  
Host Origin ◽  
Serious Disease

Anthracnose basal rot (ABR) is a serious disease of turfgrasses that is caused by the pathogen Colletotrichum graminicola. The relationships of isolates causing ABR on turfgrasses to those causing disease on important crop hosts (maize, sorghum) remain unresolved. Genetic variation among isolates from annual bluegrass, creeping bentgrass, maize, and sorghum was evaluated based on host origin and geographic origin. Isozymes were used to estimate the genetic variation of the isolates. Five enzyme systems comprising 16 alleles from 5 loci were used. Allele frequencies, genetic distance, and linkage disequilibrium values were calculated for isolates based on both host and geographic origin. Isolates from creeping bentgrass and annual bluegrass were the most closely related based on Nei's genetic distance, while isolates from maize and sorghum were the most distantly related, consistent with their known species-level relationship. Isolates from annual bluegrass and creeping bentgrass had different genetic distances to isolates from both maize and sorghum. Annual bluegrass isolates from different geographic regions had the smallest genetic distance values observed in this study, indicating a very close relationship regardless of geographic origin. Based on these data, it appears that host origin, not geographic origin, plays a more important role in the genetic diversity of these fungi.

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 Climatic Refugia and Geographical Isolation Contribute to the Speciation and Genetic Divergence in Himalayan-Hengduan Tree Peonies (Paeonia delavayi and Paeonia ludlowii)

2021 ◽  
Vol 11 ◽  
Author(s):  
Yu-Juan Zhao ◽  
Gen-Shen Yin ◽  
Yue-Zhi Pan ◽  
Bo Tian ◽  
Xun Gong
Keyword(s):  
Genetic Variation ◽  
Late Quaternary ◽  
Demographic History ◽  
Nuclear Gene ◽  
Genetic Distances ◽  
Population Divergence ◽  
Widespread Species ◽  
Isolation With Migration ◽  
Isolation By Environment ◽  
Paeonia Delavayi

Himalaya and Hengduan Mountains (HHM) is a biodiversity hotspot, and very rich in endemic species. Previous phylogeographical studies proposed different hypotheses (vicariance and climate-driven speciation) in explaining diversification and the observed pattern of extant biodiversity, but it is likely that taxa are forming in this area in species-specific ways. Here, we reexplored the phylogenetic relationship and tested the corresponding hypotheses within Paeonia subsect. Delavayanae composed of one widespread species (Paeonia delavayi) and the other geographically confined species (Paeonia ludlowii). We gathered genetic variation data at three chloroplast DNA fragments and one nuclear gene from 335 individuals of 34 populations sampled from HHM. We performed a combination of population genetic summary statistics, isolation-with-migration divergence models, isolation by environment, and demographic history analyses. We found evidence for the current taxonomic treatment that P. ludlowii and P. delavayi are two different species with significant genetic differentiation. The significant isolation by environment was revealed within all sampled populations but genetic distances only explained by geographical distances within P. delavayi populations. The results of population divergence models and demographic history analyses indicated a progenitor–derivative relationship and the Late Quaternary divergence without gene flow between them. The coalescence of all sampled cpDNA haplotypes could date to the Late Miocene, and P. delavayi populations probably underwent a severe bottleneck in population size during the last glacial period. Genetic variation in Paeonia subsect. Delavayanae is associated with geographical and environmental distances. These findings point to the importance of geological and climatic changes as causes of the speciation event and lineage diversification within Paeonia subsect. Delavayanae.

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