Genetic structure and variability in Pinusstrobus in Quebec

1994 ◽  
Vol 24 (8) ◽  
pp. 1726-1733 ◽  
Author(s):  
J. Beaulieu ◽  
J.-P. Simon
Keyword(s):  
Genetic Diversity ◽  
Statistical Tests ◽  
Natural Populations ◽  
Genetic Distances ◽  
White Pine ◽  
Eastern White Pine ◽  
Improvement Program ◽  
Bonferroni Procedure ◽  
Natural Range ◽  
Very High

The level of genetic diversity of natural populations of eastern white pine (Pinusstrobus L.) from Quebec was estimated from allozyme variants of 18 loci coding 12 enzyme systems. On average, a white pine population was polymorphic at 50.6% of loci, had 1.96 alleles and 1.22 effective alleles per locus, and observed and expected heterozygosities of 0.176 and 0.180, respectively. The level of genetic diversity was lower in the populations of the St. Lawrence lowlands than in those of western Quebec. This observation will help in guiding the selection program of the eastern white pine improvement program under way in Quebec. Genetic differentiation among sampled populations was weak and accounted for only 2% of the total diversity. The estimate of gene flow was very high, resulting in low values for genetic distances among populations. Only one locus showed a heterogeneity of allelic frequencies among populations after the Bonferroni procedure was applied for simultaneous statistical tests. A cluster analysis based on genetic distances among populations revealed that the Anticosti and Abitibi populations, located at the limit of the natural range of white pine, were similar to populations from regions that were geographically the most distant.

Genetic diversity and population structure of disjunct Newfoundland and central Ontario populations of eastern white pine (Pinus strobus)

1998 ◽  
Vol 76 (3) ◽  
pp. 500-508 ◽  
Author(s):  
Om P Rajora ◽  
Linda DeVerno ◽  
Alex Mosseler ◽  
David J Innes
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Pinus Strobus ◽  
Population Bottleneck ◽  
Genetic Distances ◽  
Population Variation ◽  
White Pine ◽  
Eastern White Pine ◽  
Genetic Diversity And Structure ◽  
Allozyme Loci

The dramatic decline of eastern white pine (Pinus strobus L.) populations in Newfoundland over the past 100 years presents an opportunity to determine and monitor population bottleneck effects on genetic diversity in trees. To provide benchmarks and indicators for monitoring genetic changes due to recent and future bottleneck events and to assist development of conservation strategies, we assessed genetic diversity and structure of six small, isolated white pine populations from two regions at the limits of its geographical range in Newfoundland for comparison with three populations from its central range in Ontario for 20 allozyme loci coding for 12 enzymes. On average, 47.8% of the loci were polymorphic, the number of alleles per locus was 1.75, and the observed and expected heterozygosities were 0.215 and 0.195, respectively. Although most of the alleles were widespread, unique alleles were found in three of the nine populations examined. The Newfoundland populations were as genetically variable as those from Ontario. Generally, all populations exhibited slight excess of heterozygotes at most loci. Only 6.1% of the detected genetic variation was among populations, and the remainder among individuals within populations. The genetic distances among the populations within a province or region were as great as those among populations between the provinces or regions. Canonical discriminant functions and cluster analysis from genetic distances separated nine populations into the same four groups. Neither provincial nor regional or geographic gradient-related patterns of population variation and differentiation were apparent. It appears that 8000 years of postglacial geographic isolation and recent population decline have had little or no detectable effect on genetic diversity or differentiation of disjunct Newfoundland white pine populations from their ancestral mainland populations. Assuming their adaptability, the Ontario seed sources may be acceptable for white pine restoration in Newfoundland.Key words : Pinus strobus, allozymes, gene conservation, genetic diversity and population structure, genetic drift, population bottleneck.

scholarly journals Genetic diversity and differentiation in reef-buildingMilleporaspecies, as revealed by cross-species amplification of fifteen novel microsatellite loci

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2936 ◽  
Author(s):  
Caroline E. Dubé ◽  
Serge Planes ◽  
Yuxiang Zhou ◽  
Véronique Berteaux-Lecellier ◽  
Emilie Boissin
Keyword(s):  
Genetic Diversity ◽  
Microsatellite Markers ◽  
Microsatellite Loci ◽  
Natural Populations ◽  
454 Sequencing ◽  
Genetic Distances ◽  
Null Alleles ◽  
Future Research ◽  
Significant Linkage ◽  
Pacific Species

Quantifying the genetic diversity in natural populations is crucial to address ecological and evolutionary questions. Despite recent advances in whole-genome sequencing, microsatellite markers have remained one of the most powerful tools for a myriad of population genetic approaches. Here, we used the 454 sequencing technique to develop microsatellite loci in the fire coralMillepora platyphylla, an important reef-builder of Indo-Pacific reefs.We tested the cross-species amplification of these loci in five other species of the genusMilleporaand analysed its success in correlation with the genetic distances between species using mitochondrial 16S sequences. We succeeded in discovering fifteen microsatellite loci in our target speciesM. platyphylla,among which twelve were polymorphic with 2–13 alleles and a mean observed heterozygosity of 0.411. Cross-species amplification in the five otherMilleporaspecies revealed a high probability of amplification success (71%) and polymorphism (59%) of the loci. Our results show no evidence of decreased heterozygosity with increasing genetic distance. However, only one locus enabled measures of genetic diversity in the Caribbean speciesM. complanatadue to high proportions of null alleles for most of the microsatellites. This result indicates that our novel markers may only be useful for the Indo-Pacific species ofMillepora.Measures of genetic diversity revealed significant linkage disequilibrium, moderate levels of observed heterozygosity (0.323–0.496) and heterozygote deficiencies for the Indo-Pacific species. The accessibility to new polymorphic microsatellite markers for hydrozoanMilleporaspecies creates new opportunities for future research on processes driving the complexity of their colonisation success on many Indo-Pacific reefs.

Variation in cone morphology and seed characters in Pinus strobus in Quebec

1995 ◽  
Vol 73 (2) ◽  
pp. 262-271 ◽  
Author(s):  
Jean Beaulieu ◽  
Jean-Pierre Simon
Keyword(s):  
Natural Populations ◽  
Pinus Strobus ◽  
White Pine ◽  
Ottawa River ◽  
River Region ◽  
Natural Range ◽  
Anticosti Island ◽  
Genotypic Control ◽  
Two Populations ◽  
Cone Scale

To investigate the patterns of variation in white pine (Pinus strobus L.), 10 natural populations from Quebec were compared using the phenotypic variation of cone and seed traits. Eight characters were measured on 10 cones collected from 30 trees in each of the 10 sampled populations. Four populations were from the Ottawa River region and four from the St. Lawrence Lowlands region, while two populations were at the margin of the natural range of the species in Quebec, from the Abitibi region and Anticosti Island. Significant differences among populations were detected for each character. Estimates of repeatability of these traits were relatively high, suggesting substantial genotypic control over them. These estimates were consistent from population to population. Results of multivariate analyses suggest that populations from the Ottawa River region are similar to those from the St. Lawrence region, with populations from these regions diverging only in cone scale length. However, populations from the St. Lawrence region were more distinct from each other than those from the Ottawa River region. The population from Abitibi deviates considerably from the other populations, suggesting habitat-selection pressures acting at the margin of the natural range of the species under continental conditions. Finally, no general geographical trend was detected in the observed variation. Key words: white pine, morphology, cone, seed, variation.

scholarly journals Morphological and Isozyme Variation in Natural Populations of the Genus Medicago L. Prospected in Northern Algeria

2015 ◽  
Vol 43 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Imane MEDOUKALI ◽  
Ines BELLIL ◽  
Douadi KHELIFI
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
Morphological Characteristics ◽  
Genetic Distances ◽  
Glutamate Oxaloacetate Transaminase ◽  
High Genetic Diversity ◽  
Isozyme Markers ◽  
Northern Algeria ◽  
Isozyme Variability ◽  
High Level

As part of the evaluation and enhancement of genetic resources, morphological and isozyme variability within and among 169 accessions, representing 14 species of the genus Medicago L. collected in northern Algeria, was assessed using twelve quantitative traits and two enzymatic systems. Phenotype frequencies were scored in six enzyme zones to determine isozyme variability within and among populations. The data analysis resolved a high level of genetic diversity. Ten morphometric characteristics contributed to the discrimination of the species. The relationship between the collection site environment and phenotypic characteristics was also studied. Esterase (EST) enzyme system was more polymorphic than glutamate oxaloacetate transaminase (GOT) system. Were scored 2 zones with 10 bands and 21 phenotypes for GOT (glutamate oxaloacetate transaminase) and 4 zones with 22 bands and 71 phenotypes for EST (esterase) Polymorphism index and Jaccard’s genetic distances revealed the existence of a high genetic diversity within and among the studied populations. The annual species M. polymorpha presented an intraspecific polymorphism index of 0.57, which was higher than all other species indices. Clustering of the species based on isozyme markers was in agreement with taxonomic criteria and showed no significant correlation with morphological characteristics. Conservation programs should take into account the level of genetic diversity within and between populations revealed by isozyme markers.

High genetic diversity, distant phylogenetic relationships and intraspecies recombination events among natural populations of Yam mosaic virus: a contribution to understanding potyvirus evolution

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 243-255 ◽  
Author(s):  
M. Bousalem ◽  
E. J. P. Douzery ◽  
D. Fargette
Keyword(s):  
Genetic Diversity ◽  
Mosaic Virus ◽  
Statistical Tests ◽  
Phylogenetic Analyses ◽  
Natural Populations ◽  
High Genetic Diversity ◽  
Single Clade ◽  
Cultivated Species ◽  
Selection Of

To evaluate the genetic diversity and understand the evolution of Yam mosaic virus (YMV), a highly destructive pathogen of yam (Dioscorea sp.), sequencing was carried out of the C-terminal part of the replicase (NIb), the coat protein (CP) and the 3′-untranslated region (3′-UTR) of 27 YMV isolates collected from the three main cultivated species (Dioscorea alata, the complex Dioscorea cayenensis–Dioscorea rotundata and Dioscorea trifida). YMV showed the most variable CP relative to eight other potyviruses. This high variability was structured into nine distant molecular groups, as revealed by phylogenetic analyses and validated by assessment of the molecular evolutionary noise. No correlation was observed between the CP and 3′-UTR diversities and phylogenies. The most diversified and divergent groups included isolates from Africa. The remaining groups clustered in a single clade and a geographical distinction between isolates from the Caribbean, South America and Africa was observed. The role of the host in the selection of particular isolates was illustrated by the case of a divergent cultivar from Burkina Faso. Phylogenetic topological incongruence and complementary statistical tests highlighted the fact that recombination events, with single and multiple crossover sites, largely contributed to the evolution of YMV. We hypothesise an African origin of YMV from the yam complex D. cayenensis–D. rotundata, followed by independent transfers to D. alata and D. trifida during virus evolution.

scholarly journals Genetic diversity and structure of domestic cavy (Cavia porcellus) populations from smallholder farms in southern Cameroon

2017 ◽  
Vol 19 (1) ◽  
pp. 1 ◽  
Author(s):  
Basengere Ayagirwe ◽  
Felix Meutchieye ◽  
Appolinaire Djikeng ◽  
Robert Skilton ◽  
Sarah Osama ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Relatedness ◽  
Genetic Distances ◽  
Sub Saharan Africa ◽  
High Rate ◽  
Improvement Program ◽  
Littoral Region ◽  
Genetic Diversity And Structure ◽  
Southern Cameroon

Although domestic cavies are widely used in sub-Saharan Africa as a source of meat and income, there are only a few studies of their population structure and genetic relatedness. This seminal study was designed with the main objective to assess the genetic diversity and determine the population structure of cavy populations from Cameroon to guide the development of a cavy improvement program. Sixteen microsatellite markers were used to genotype 109 individuals from five cavy populations (Wouri, Moungo and Nkongsamba in the Littoral region, and Mémé and Fako in the Southwest region of Cameroon). Twelve markers worked in the five populations with a total of 17 alleles identified, with a range of 2.9 to 4.0 alleles per locus. Observed heterozygosity (from 0.022 to 0.277) among populations was lower than expected heterozygosity (from 0.42 to 0.54). Inbreeding rates between individuals of the populations and between individuals in each population were 59.3% and 57.2%, respectively, against a moderate differentiation rate of 4.9%. All the tested loci deviated from Hardy-Weinberg equilibrium, except for locus 3. Genetic distances between populations were small (from 0.008 to 0.277), with a high rate of variability among individuals within each population (54.4%). Three distinct genetic groups were structured. This study has shown that microsatellites are useful for the genetic characterization of cavy populations in Cameroon and that the populations investigated have sufficient genetic diversity that can be used to be deployed as a basis for weight, prolificacy and disease resistance improvement. The genetic of diversity in Southern Cameroon is wide and constitute an opportunity for cavy breeding program. 

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.

Mating system in natural populations of eastern white pine in Quebec

1995 ◽  
Vol 25 (10) ◽  
pp. 1697-1703 ◽  
Author(s):  
J. Beaulieu ◽  
J.-P. Simon
Keyword(s):  
Family Structure ◽  
Mating System ◽  
Natural Populations ◽  
Outcrossing Rate ◽  
The Other ◽  
Single Locus ◽  
White Pine ◽  
Eastern White Pine ◽  
Gene Frequencies ◽  
Self Fertilization

The mating system in two natural eastern white pine (Pinusstrobus L.) populations in Quebec was investigated. These populations contrasted in density and age. The single-locus as well as multilocus outcrossing rate estimates were obtained from four polymorphic enzyme loci using open-pollinated progeny data. The single-locus outcrossing rates ranged from 0.934 to 1.110 with a mean of 1.026 in one population and varied from 0.862 to 1.186 with a mean of 1.007 in the other population. Multilocus estimates exceeded 1.0 in both populations, suggesting the possible absence of self-fertilization. Pollen pool gene frequencies were homogeneous in one population and heterogeneous in the other. The positive or less negative F-values found in the filial populations compared with those observed in the parental populations suggest the presence of a family structure favouring consanguineous matings.

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