Enzyme variation in natural populations of Sitka spruce (Piceasitchensis). 1. Genetic variation patterns among trees from 10 IUFRO provenances

1980 ◽  
Vol 10 (3) ◽  
pp. 415-422 ◽  
Author(s):  
Francis C. Yeh ◽  
Yousry A. El-Kassaby
Keyword(s):  
Genetic Variation ◽  
Gene Diversity ◽  
Natural Populations ◽  
Sitka Spruce ◽  
Genetic Distances ◽  
Pairwise Comparisons ◽  
A Value ◽  
Variation Patterns ◽  
Average Proportion ◽  
Geographic Sources

Genetic variation at 24 enzyme loci was studied for 10 IUFRO populations of Sitka spruce (Piceasitchensis (Bong.) Carr.). The average proportion of polymorphic loci per population was 0.51 ± 0.02 and the average proportion of heterozygous loci per individual was 0.15 ± 0.03. The following generalizations were advanced: (1) the amount of genetic polymorphism varied considerably from locus to locus; (2) many populations were similar in the amount and pattern of genetic variation for most loci; (3) but some loci had large differences among populations.Eight percent of the gene diversity was attributed to interpopulation differentiation; 92% of the total gene diversity resided within populations. Pairwise comparisons of genetic distances averaged 0.014, a value which reflected very little differentiation between geographic sources.

scholarly journals RAPD ANALYSIS OF GENETIC VARIATION IN NATURAL POPULATIONS OF AEGILOPS SP. FROM SOUTH ADRIATIC

AGROFOR ◽  
2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Miodrag DIMITRIJEVIĆ ◽  
Sofija PETROVIĆ ◽  
Borislav BANJAC ◽  
Goran BARAĆ
Keyword(s):  
Genetic Variation ◽  
Food Production ◽  
Rapd Markers ◽  
Rapd Analysis ◽  
Gene Diversity ◽  
Rapd Marker ◽  
Natural Populations ◽  
Genetic Structuring ◽  
Potential Source ◽  
Novel Approach

New challenges that food production is facing, requires novel approach inagricultural strategy. The scissors of growing demand for food and the limits of theEarth's resources are forcing plant breeders to run for the new borders, utilizing allthe available genetic variation in order to create fruitful and economically soundcultivars. Aegilops sp. (Poaceae) is a potential source of genetic variation for wheatimprovement. RAPD marker analysis was used in order to distinguish and evaluatedifferent genotypes of Aegilops sp. population samples from the collectiongathered during few years’ expeditions in South Adriatic, along the coastal, littoraland the inland parts of Montenegro. Ten randomly amplified polymorphic DNAmarkers (RAPDs) were tested: OPA-05, OPA-08, OPB-06, OPA-02, OPA-07,OPA-25, OPB-07, OPB-18, OPC-06, OPC-10 to examine genetic structuring on 18samples of 6 populations of different Aegilops sp. According to global AMOVA,75% of total gene diversity was attributable mostly to diversity within population(ΦPT =0.205 p=0.001), indicating that the groups of studied goat grass populationswere seemingly to differing genetically. In contrast, 25% of the variation camefrom variation among populations. According to PCoA, the distribution of 18 goatgrass accessions by Principal Coordinate Analysis shows 3 distinct groups. PCoaxis 1, PCo axis 2, and PCo axis 3 account for 20.8%, 18.2% and 14.1% of thevariation, respectively. The results showed that RAPD markers could be aconvenient tool for investigating genetic variation and for detecting geneticstructuring of populations. Genetic variability formed under natural selection wasentrenched.

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.

On Some Theoretical Studies on Gene Differentiation in Natural Populations

1975 ◽  
Vol 24 (1-2) ◽  
pp. 111-117
Author(s):  
Ranajit Chakraborty
Keyword(s):  
Genetic Variation ◽  
Genetic Drift ◽  
Molecular Level ◽  
Gene Diversity ◽  
Natural Populations ◽  
Simultaneous Action ◽  
Present Moment ◽  
Theoretical Studies ◽  
Random Genetic Drift ◽  
Approaches To Study

Different mathematical approaches to study the extent of genetic variation of natural populations are reviewed. The modern understanding of the gene structure permits new interpretations of existing concepts like fixation or inbreeding. A more recent measure of genie divergence, which at molecular level is designed to measure net codon differences is also seen to be related with gene diversity in a substructed population. It is argued that such variations are produced and preserved possibly by simultaneous action of migration, mutation, selection, and random genetic drift. At the present moment it is very difficult to isolate out the effect of each factor because of varying degrees of variation at the different gene sites and between different sets of populations.

scholarly journals Genetic Diversity of Seven Deciduous Azalea Species (Rhododendron spp. section Pentanthera) Native to the Eastern United States

2008 ◽  
Vol 133 (3) ◽  
pp. 374-382 ◽  
Author(s):  
Matthew Chappell ◽  
Carol Robacker ◽  
Tracie M. Jenkins
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Diversity ◽  
Interspecific Variation ◽  
Genetic Distances ◽  
Anthropogenic Activity ◽  
Group Method ◽  
Aflp Analysis ◽  
Eastern United States

Despite the ecologic and economic importance of native deciduous azaleas (Rhododendron L. section Pentanthera G. Don), our understanding of interspecific variation of North American deciduous azalea species comes principally from morphologic studies. Furthermore, little is known concerning intraspecific or interpopulation genetic variation. With ever-increasing loss and fragmentation of native azalea habitat in the eastern United States due to anthropogenic activity, it is imperative that an understanding of natural genetic variation among and within species and populations is acquired. The present study addresses questions of genetic diversity through the use of amplified fragment length polymorphism (AFLP) analysis. Twenty-five populations of seven species of native azalea were analyzed using three primer pairs that amplified a total of 417 bands. Based on analysis of molecular variance (AMOVA) and estimates of Nei's coefficients of gene diversity (H S, H T, and G ST), the majority of variation found in deciduous azalea occurs within populations. Variation both among species and among population was low, likely the effect of common ancestry as well as frequent introgression among members (and populations) of section Pentanthera. The latter was evident in four populations of R. prunifolium (Small) Millais and R. canescens (Michaux) Sweet that were highly related to R. austrinum (Small) Rehder and R. viscosum (L.) Torrey, respectively. Despite these outliers, most populations were grouped into species based on Nei's unbiased genetic distances viewed as an unweighted pair group method with arithmetic mean (UPGMA) phenogram. The significance of these results is discussed in relation to breeding in section Pentanthera.

scholarly journals Genetic diversity analysis of tropical sugar beet (Beta vulgaris L.) varieties in Bangladesh using RAPD markers

Genetika ◽  
2016 ◽  
Vol 48 (1) ◽  
pp. 151-164
Author(s):  
Saidin Saclain ◽  
Abdul Latif ◽  
Babul Bala ◽  
Mithun Mallik ◽  
Shahidul Islam
Keyword(s):  
Genetic Variation ◽  
Sugar Beet ◽  
Genetic Distance ◽  
Rapd Markers ◽  
Gene Diversity ◽  
Similarity Index ◽  
Genetic Distances ◽  
Group Method ◽  
Pair Group ◽  
Major Cluster

Knowledge on intra-specific genetic variation of an organism is important for its genetic improvement and conservation. In order to estimate genetic variation and relatedness in eleven tropical Sugar beet varieties we used randomly amplified polymorphic DNA (RAPD) markers. The RAPD analysis was performed using six decamer random primers, which amplified a total of 63 DNA fragments of which 43 (68.25%) were found polymorphic. The average polymorphic bands per primer was 7.17 and the overall gene diversity was 0.24. Among the 43 polymorphic loci studied, 2 were specific for 2K 310, 1 for Shubraha, 1 for Natura and 1 for HI-0473 varieties. Pair wise genetic distance and similarity indices were ranged from 0.12-0.51 and 66.73-92.91, respectively. Cauvery and 2K 310 were found to be the most distantly related with a higher genetic distance value (GD = 0.51) and lower similarity index (SI = 66.73), while Aranka and Serenada were the most closely related with their lower GD (0.12) and higher SI(92.91) values. In an unweighted pair group method of arithmetic mean dendrogram constructed on the basis of genetic distances, the eleven varieties grouped into two main clusters: 2K 310 alone was in one cluster whereas 10 other varieties grouped into a major cluster. This indicates that 2K 310 was distantly related with each of the other varieties. Distantly related varieties based on estimated genetic variation could be selected for future breeding program that could result in improvement of this crop.

Temporal components of genetic variation in migrating and wintering American wigeon

1993 ◽  
Vol 71 (11) ◽  
pp. 2229-2235 ◽  
Author(s):  
Olin E. Rhodes Jr. ◽  
Loren M. Smith ◽  
Ronald K. Chesser
Keyword(s):  
Genetic Variation ◽  
Gene Diversity ◽  
High Plains ◽  
Genetic Characteristics ◽  
Total Genetic Variation ◽  
Breeding Populations ◽  
Wintering Waterfowl ◽  
Breeding Grounds ◽  
Average Proportion ◽  
Wintering Population

Data from allele frequencies of wintering American wigeon (Anas americana) from the Southern High Plains (SHP) of Texas were used to monitor changes in genetic characteristics of the wintering population through time, and to estimate the average proportion of total genetic variation partitioned among parent breeding populations. Wigeon were surveyed electrophoretically for genetic variation at 25 biochemical loci. Changes in total gene diversity were observed throughout the study period (5 October 1988 to 15 March 1989) at numerous loci. Significant temporal changes in the genetic composition of the wintering population were detected, and a minimum of 7% of the total genetic variation in these wigeon was thought to be partitioned among the breeding populations represented on the SHP. A new influx of migrating wigeon, weather-related movements of wigeon, or spatial subdivision of breeding populations on the SHP may be responsible for shifts observed in the genetic characteristics of the wintering population. Significant heterozygote deficiencies in the sample of wintering wigeon suggest that this species maintains some degree of genetic structure on the breeding grounds. Genetic data collected from wintering waterfowl may provide minimum expectations of the degree of genetic subdivision among breeding populations and may help waterfowl biologists to detect changes in the composition of wintering waterfowl populations through time.

scholarly journals GENETIC VARIATION IN NATURAL POPULATIONS OF FIVE DROSOPHILA SPECIES AND THE HYPOTHESIS OF THE SELECTIVE NEUTRALITY OF PROTEIN POLYMORPHISMS

Genetics ◽  
1974 ◽  
Vol 77 (2) ◽  
pp. 343-384
Author(s):  
Francisco J Ayala ◽  
Martin L Tracey ◽  
Lorraine G Barr ◽  
John F McDonald ◽  
Santiago Pérez-Salas
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Natural Populations ◽  
Evolutionary Divergence ◽  
Average Value ◽  
Local Populations ◽  
Selective Neutrality ◽  
Average Proportion ◽  
Substantial Degree ◽  
Protein Polymorphisms

ABSTRACT We have studied genetic variation at 30-32 loci coding for enzymes in natural populations of five species of Drosophila. The average proportion of heterozygous loci per individual is 17.7 ± 0.4%. The average proportion of polymorphic loci per population is 69.2 ± 2.6% or 49.8 ± 2.2%, depending on what criterion of polymorphism is used. The following generalizations are advanced: (1) The amount of genetic polymorphism varies considerably from locus to locus. (2) At a given locus, populations of the same species are very similar in the amount and pattern of genetic variation. (3) However, at some loci large differences sometimes occur between local populations of the same species. (4) The amount of variation at a given locus is approximately the same in all five species. (5) When different species are compared, the pattern of the variation is either essentially identical or totally different at a majority of loci. We have tested the hypothesis that protein polymorphisms are selectively neutral by examining four predictions derived from the hypothesis. Our results are at variance with every one of the predictions. We have measured the amount of genetic differentiation, D, between taxa of various degrees of evolutionary divergence. The average value of D is 0.033 for local populations, 0.228 for subspecies, 0.226 for semispecies, 0.538 for sibling species, and 1.214 for morphologically distinguishable species. Our results indicate that a substantial degree of genetic differentiation (22.8 allelic substitutions for every 100 loci) occurs between allopatric populations that have diverged to the point where they might become different species if they were to become sympatric. However, very little additional genetic change is required for the development of complete reproductive isolation. After the speciation process is completed, species continue to diverge genetically from each other.

scholarly journals Genetic Structure and Variability of Natural Populations of Maritime Pine (Pinus pinaster Aiton) in Morocco

2004 ◽  
Vol 53 (1-6) ◽  
pp. 93-99 ◽  
Author(s):  
N. Wahid ◽  
S. C. González-Martínez ◽  
I. El Hadrami ◽  
A. Boulli
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Genetic Structure ◽  
Gene Diversity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Natural Populations ◽  
Genetic Distances ◽  
Maritime Pine ◽  
High Atlas ◽  
Middle Atlas

Abstract The estimation of genetic diversity using molecular markers is a major component of genetic conservation programs. In its range, Maritime pine has been extensively studied using different molecular markers and quantitative traits. However, Moroccan populations have been usually represented only by a few typical locations in the Middle Atlas (e.g., Tamjout). To describe the genetic structure and variability of maritime pine in Morocco, eleven populations of this species comprising all major geographic regions (Rif, Middle Atlas and High Atlas) were studied using allozyme markers. A total of 471 samples were analyzed using polyacrylamide gel electrophoresis (PAGE) of eight enzyme systems encoded by 19 loci. Genetic variation was lower in Morocco than in other ranges of the species. However, genetic diversity was structured and a high differentiation among populations (θ = 10.44%) and a moderate correlation between genetic and geographic distances were found (0.350). Three main groups of populations can be distinguished based on genetic distances: (i) Mediterranean Coastal, (ii) Occidental Rif and Middle Atlas and (iii) High Atlas. The populations from Middle Atlas presented the lowest values of allelic richness and gene diversity whereas the populations from Rif showed a considerable amount of genetic variability. Human impact and isolation are major factors explaining population genetic structure of maritime pine in Morocco. Overexploitation of the forest by intensive cattle grazing and land speculation are suggested to be active mechanisms currently deploying the genetic resources of this species.

scholarly journals RAPD analysis of the genetic diversity of two natural populations of Paphiopedilum villosum var. Annamense rolfe. in the Lam Vien plateau

2016 ◽  
Vol 14 (3) ◽  
pp. 451-459
Author(s):  
Đặng Thị Thắm ◽  
Nông Văn Duy ◽  
Trần Văn Tiến ◽  
Lê Ngọc Triệu ◽  
Khuất Hữu Trung ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Wild Population ◽  
Gene Diversity ◽  
Species Conservation ◽  
Natural Populations ◽  
Small Population ◽  
Habitat Destruction ◽  
Similarity Coefficients ◽  
Population Sizes ◽  
Two Populations

Paphiopedilum villosum var. annamense Rolfe. is the attractive pot plant characterize by its larger and beautiful flower. Wild population of that orchid are now considered to be rare in nature as a result of habitat destruction and commercial preference. Thus, it is very important that actions should be taken to conserve this orchid before it becomes extinct. The information of genetic variation at both population and species levels is a scientific basic for species conservation. In this research, two populations of Paphiopedilum villosum var. annamense Rolfe were collected in Lam Dong province, Vietnam for analysing of genetic variation. RAPD directive was used to examine genetic variability in 20 individuals of two populations. The results showed that 25 bands were recorded from 12 specific identification primers. The percentages of polymorphic loci at species and population levels in the research were not high (Pt = 74.07%; P1 = 67.90%; P2 = 62.35%). However, in the first population, a higher percentage of polimorphic loci was observed as in the second one. Significant heterozygosity at both population and species levels was also low (HE1 = 0.23; HE2 = 0.18; and HEt = 0.25). The total gene diversity at the species level was partitioned primarily between two populations, as show by low GST= 0.17. Genetic distance between two populations was low (D12 = 0.079). In the orther hand, Genetic similarity coefficients between individuals in the general population were ranged from 0.57 to 0.91. The results suggested that the small population sizes in isolation had led to increase of inbred individuals within populations. Some solutions to the conservation and sustainable development have been mentioned.

scholarly journals Genetic variability of three natural populations of Maytenus aquifolium (Celesteraceae) from Telêmaco Borba, Paraná, Brazil

2010 ◽  
Vol 53 (5) ◽  
pp. 1037-1042 ◽  
Author(s):  
Sandra Aparecida Sahyun ◽  
Eduardo Augusto Ruas ◽  
Claudete de Fátima Ruas ◽  
Cristiano Medri ◽  
José Roberto Pinto de Souza ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Bayesian Analysis ◽  
Rapd Markers ◽  
Gene Diversity ◽  
Natural Populations ◽  
Soil Types ◽  
Number Of Clusters ◽  
Analysis Of Molecular Variance ◽  
Molecular Variance

Three populations of Maytenus aquifolium from Monte Alegre farm, Telemaco Borba county, Paraná, Brazil were analyzed by RAPD markers. A total of 13 primers were applied wich yielded 283 well amplified markers in all the studied populations (Mortandade, Vila Preta and Trinita), producing different values of gene diversity and polymorphic loci. The analysis of molecular variance (AMOVA) indicated that 21.77% of the genetic variation was among the population. Pairwise F ST analysis showed that the most divergent populations were closer geographically, demonstrating that other factors such as different soil types could explain this variation. Bayesian analysis for K number of clusters and the Principal Coordinate indicated that these three populations were highly structured, corroborating the high values found for the F ST and indicating that for conservation purposes all populations should be maintained.

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