Genetic Differentiation in Natural Populations of Grevillea robusta

1997 ◽  
Vol 45 (4) ◽  
pp. 669 ◽  
Author(s):  
C. E. Harwood ◽  
G. F. Moran ◽  
J. C. Bell
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Natural Populations ◽  
Grevillea Robusta ◽  
Distance Analysis ◽  
Riverine Habitat ◽  
Natural Range ◽  
Isozyme Loci ◽  
The Difference ◽  
Genetic Distance Analysis

Genetic variation in 23 natural populations of Grevillea robusta A.Cunn. from across the natural range of the species was examined using 20 isozyme loci assayed in young seedlings. Mean expected heterozygosity per population, He , varied from 0.080 to 0.131 with an average of 0.105. The genetic diversity of individual populations did not appear to be related to their ecological characteristics (araucarian vine forest or riverine habitat types) or their geographic locations. A genetic distance analysis indicated a significant separation of the populations into two regional groups, eight from the northern part of the natural range and the remaining 15 from central and southern areas. Between-population differences accounted for 17.9% of the total genetic variation, one-third of which was attributable to the difference between the two regional groups. Most alleles at the 20 loci occurred across most or all of the geographic range. This, and the low level of genetic differentiation between populations, suggest that genetic exchange between populations has been maintained, despite the pattern of natural distribution of the species in small, separated populations.

scholarly journals Spatial Structure and Genetic Variation of a Mangrove Species (Avicennia marina (Forssk.) Vierh) in the Farasan Archipelago

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1287
Author(s):  
Rahmah N. Al-Qthanin ◽  
Samah A. Alharbi
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Species Conservation ◽  
Natural Populations ◽  
Avicennia Marina ◽  
Conservation Strategies ◽  
Isolated Populations ◽  
Mangrove Species ◽  
Population Genetic Differentiation ◽  
Sea Currents

Avicennia marina (Forssk.) Vierh is distributed in patches along the Farasan archipelago coast and is the most common mangrove species in the Red Sea. However, to date, no studies have been directed towards understanding its genetic variation in the Farasan archipelago. In this investigation, genetic variations within and among natural populations of Avicennia marina in the Farasan archipelago were studied using 15 microsatellite markers. The study found 142 alleles on 15 loci in nine populations. The observed (Ho) and expected (He) heterozygosity values were 0.351 and 0.391, respectively, which are much lower than those of earlier studies on A. marina in the Arabian Gulf. An inbreeding effect from self-pollination might explain its heterozygote deficiency. Population genetic differentiation (FST = 0.301) was similar to other mangrove species. Our findings suggest that the sea current direction and coastal geomorphology might affect genetic dispersal of A. marina. The more isolated populations with fewer connections by sea currents exhibited lower genetic variation and differentiation between populations. The genetic clustering of populations fell into three main groups—Group 1 (populations of Farasan Alkabir Island), Group 2 (populations of Sajid Island), and Group 3 (mix of one population of Farasan Alkabir Island and a population of Zifaf Island). More genetic variation and less genetic differentiation occurred when the population was not isolated and had a direct connection with sea currents. Both of these factors contributed to limited propagule dispersal and produced significant structures among the population. It is expected that the results of this research will be useful in determining policy and species-conservation strategies and in the rehabilitation of A. marina mangrove stands on the Farasan islands in an effort to save this significant natural resource.

scholarly journals Genetic Differentiation in Moroccan Opuntia ficus-indica Cultivars Using Simple Sequence Repeat (SSR) Markers

2016 ◽  
Vol 8 (3) ◽  
pp. 380-385 ◽  
Author(s):  
Aissam EL FINTI ◽  
Driss TALIBI ◽  
Mouhamed SIDKI ◽  
Abdelhamid E. MOUSADIK
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Ssr Markers ◽  
Opuntia Ficus Indica ◽  
Distance Analysis ◽  
Reference Collection ◽  
Ssr Loci ◽  
Set Up ◽  
Genetic Distance Analysis ◽  
Simple Sequence

Estimation of genetic parameters at SSR loci can be applied for assessing the differences between cultivars or populations, either for variety distinction or the management of genetic resources. In this study, 13 Opuntia ficus-indica cultivars were analyzed using 10 SSR markers selected for studying the genetic diversity among these chosen cultivars. Over the 10 SSR markers, a total of 45 reproducible bands were scored with an average of 4.5 alleles/locus, while the observed heterozygosity (Ho) values of amplified loci ranged from 0.15 (SSR1) to 0.92 (SSR2 and SSR 11). Genetic distance analysis of the 13 cultivars showed a large genetic differentiation (GST = 0.47) and high number of different groups. Most of the accessions were not found to be clustered according to their eco-geographical origin. In addition, each cultivar was characterized by its own multiallelic combination between loci. The results revealed the usefulness of SSR in understanding of genetic diversity in Moroccans Barbary fig cultivars, thus being helpful to set up rational decisions concerning the establishment of a national reference collection.

Genetic diversity and differentiation in populations of Japanese stone pine (Pinuspumila) in Japan

1996 ◽  
Vol 26 (8) ◽  
pp. 1454-1462 ◽  
Author(s):  
Naoki Tani ◽  
Nobuhiro Tomaru ◽  
Masayuki Araki ◽  
Kihachiro Ohba
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Phylogenetic Trees ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Group Method ◽  
Stone Pine ◽  
Arithmetic Means ◽  
Pair Group

Japanese stone pine (Pinuspumila Regel) is a dominant species characteristic of alpine zones of high mountains. Eighteen natural populations of P. pumila were studied in an effort to determine the extent and distribution of genetic diversity. The extent of genetic diversity within this species was high (HT = 0.271), and the genetic differentiation among populations was also high (GST = 0.170) compared with those of other conifers. In previous studies of P. pumila in Russia, the genetic variation within the species was also high, but the genetic differentiation among populations was low. We infer that this difference originates from differences in geographic distribution and ecological differences between the two countries. The genetic variation within each population tended, as a whole, to be smaller within marginal southern populations than within northern populations. Genetic relationships among populations reflect the geographic locations, as shown by unweighted pair-group method with arithmetic means and neighbor-joining phylogenetic trees.

scholarly journals Heritable variation in resistance to the endonuclear parasite Holospora undulata across clades of Paramecium caudatum

2020 ◽  
Author(s):  
Jared Weiler ◽  
Giacomo Zilio ◽  
Nathalie Zeballos ◽  
Louise Noergaard ◽  
Winiffer D. Conce Alberto ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Natural Populations ◽  
Infection Prevalence ◽  
Post Inoculation ◽  
Paramecium Caudatum ◽  
Heritable Variation ◽  
Natural Genetic Variation ◽  
Geographical Scale ◽  
Neutral Marker ◽  
The Difference

AbstractResistance is a key determinant in interactions between hosts and their parasites. Understanding the amount and distribution of genetic variation in this trait can provide insights into (co)evolutionary processes and their potential to shape patterns of diversity in natural populations. Using controlled inoculation in experimental mass cultures, we investigated the quantitative genetic variation in resistance to the bacterial parasite Holospora undulata across a worldwide collection of strains of its ciliate host Paramecium caudatum. We combined the observed variation with available information on the phylogeny and biogeography of the strains. We found substantial variation in resistance among strains (with broad-sense heritability > 0.5), repeatable between laboratories and ranging from total resistance to near-complete susceptibility. Early (one week post inoculation) measurements provided higher estimates of resistance heritability than did later measurements (2-3 weeks), possibly due to diverging epidemiological dynamics in replicate cultures of the same strains. Genetic distance (based on a neutral marker) was positively correlated with the difference in resistance phenotype between strains (r = 0.45), essentially reflecting differences between highly divergent clades (haplogroups) within the host species. Haplogroup A strains, mostly European, were less resistant to the parasite (49% infection prevalence) than non-European haplogroup B strains (28%). At a smaller geographical scale (within Europe), strains that are geographically closer to the parasite origin (Southern Germany) were more susceptible to infection than those from further away. These patterns are consistent with a picture of local parasite adaptation. Our study demonstrates ample natural genetic variation in resistance on which selection can act and hints at symbiont adaptation producing signatures in geographic and lineage-specific patterns of resistance in this model system.

scholarly journals Distribution of Selected Single Nucleotide Polymorphisms in the Brahmin, Rajput and Bania Populations of Jammu District of Jammu and Kashmir, North India

2021 ◽  
Vol 21 (02) ◽  
Author(s):  
S. M. S. Chahal
Keyword(s):  
Single Nucleotide Polymorphisms ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
North India ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Jammu And Kashmir ◽  
Distance Analysis ◽  
The People ◽  
Genetic Distance Analysis

ABSTRACTA total of 461 randomly selected unrelated subjects belonging to three selected castes populations of Jammu district of Jammu and Kashmir (J&K) viz., the Brahmin, Rajput, and Bania were typed using standard PCRRFLP technique for a battery of five SNPs (Single Nucleotide Polymorphisms) namely NAT2, ADH2, PSCR, T2, and ALAD. The objective of the present study was to characterize these populations genetically and assess the degree of genetic differentiation and genetic affinities among them. The results revealed that the present caste populations were moderately differentiated (GST = 0.0105).The genetic distance analysis demonstrated that the Rajput and Bania were in close genetic affinities while the Brahmin population was somewhat distant. In conclusion, the present investigation documented the underlying genomic uniformity in the people of the Jammu district.

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 Somaclonal Variation in Habanero Pepper (Capsicum chinense Jacq.) as Assessed ISSR Molecular Markers

HortScience ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 481-485 ◽  
Author(s):  
Jericó J. Bello-Bello ◽  
Lourdes G. Iglesias-Andreu ◽  
Susana A. Avilés-Viñas ◽  
Eunice Gómez-Uc ◽  
Adriana Canto-Flick ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Issr Markers ◽  
Direct Organogenesis ◽  
Capsicum Chinense ◽  
Distance Analysis ◽  
System A ◽  
Regenerated Plants ◽  
Habanero Pepper ◽  
Genetic Distance Analysis

Intersimple sequence repeat (ISSR) markers were used to evaluate the effects of in vitro culture on genetic variation in Habanero pepper (Capsicum chinense Jacq.) regeneration protocols. A total of 219 ISSR clear and reproducible fragments were generated with 13 ISSR primers in direct organogenesis, direct and indirect somatic embryos, and the embryogenic callus system. A cluster analysis was performed to express in the form of dendrogram the relationships among different regeneration systems and the genetic variability detected. Genetic distance analysis indicated that our regeneration protocols are inappropriate for micropropagation, conservation, or genetic transformation; however, they may be applicable to breeding. This is the first report on the use of molecular analysis to evaluate genetic variation of in vitro-regenerated plants of Habanero pepper using ISSR markers.

Genetic differentiation and inversion clines in Indian natural populations of Drosophila melanogaster

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 618-625 ◽  
Author(s):  
Aparup Das ◽  
B. N. Singh
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Differentiation ◽  
Natural Populations ◽  
The South ◽  
The North ◽  
Chromosome Inversions ◽  
The Difference ◽  
And Inversion ◽  
First Time ◽  
North And South

To study the genetic differentiation and inversion clines in Indian natural populations of Drosophila melanogaster, 14 natural populations (6 from the north and 8 from the south) were screened for chromosome inversions. The chromosomal analysis revealed the presence of 23 paracentric inversions, which include 4 common cosmopolitan, 4 rare cosmopolitan, 2 recurrent endemic, and 13 unique endemic (new inversions detected for the first time) inversions. The difference in karyotype frequencies between populations from the north and south were highly significant and the level of inversion heterozygosity was higher in populations from the south. Statistically significant negative correlations were found between each of the four common cosmopolitan inversions and latitude. These findings are in accord with results from other worldwide geographic regions and show that Indian populations of D. melanogaster have undergone considerable genetic differentiation at the level of inversion polymorphism.Key words: Drosophila melanogaster, Indian natural populations, chromosome inversions, genetic differentiation, north–south clines.

scholarly journals Genetic Variation Among Natural Populations of Tilletia controversa and T. bromi

2000 ◽  
Vol 90 (4) ◽  
pp. 376-383 ◽  
Author(s):  
Guillermo Pimentel ◽  
Tobin L. Peever ◽  
Lori M. Carris
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Gene Diversity ◽  
Random Amplified Polymorphic Dna ◽  
Natural Populations ◽  
Host Population ◽  
Natural Hybridization ◽  
Character State ◽  
Phenotypic Analysis ◽  
Tilletia Controversa

Isolates of Tilletia controversa and T. bromi were sampled from wheat and two Bromus species hosts, respectively, in the Pacific Northwest, and genetic variation within and among populations was determined. Fifty-one random amplified polymorphic DNA markers from eleven primers were treated as phenotypic 1 and 0 character state data to estimate similarities and analyze molecular variance (AMOVA) among populations and as putative genetic loci to carry out analyses of gene diversity. Phenotypic analysis of T. controversa and T. bromi isolates revealed two distinct clusters that were 37% similar. The T. bromi cluster was subdivided further into two groups, corresponding to host, with 40% similarity. Cluster analysis based on allele frequencies produced similar results and also supported two T. bromi groups based on host. No evidence of natural hybridization and introgression was detected between the T. controversa and T. bromi populations. Both AMOVA and gene diversity analyses detected moderate levels of differentiation among T. controversa populations, whereas T. bromi populations were highly differentiated. The level of genetic differentiation observed between the T. bromi populations on different Bromus species hosts supports the hypothesis that a high degree of host specificity exists in the wild grass-infecting smuts. We speculate that the higher level of genetic differentiation among the T. bromi populations compared with the T. controversa populations on wheat may be due to selection by a more genetically diverse host population.

scholarly journals RAPD Analysis of Genetic Variation Within and Among Four Natural Populations of Betula maximowicziana

2004 ◽  
Vol 53 (1-6) ◽  
pp. 234-239 ◽  
Author(s):  
Yoshiaki Tsuda ◽  
S. Goto ◽  
Y. Ide
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Global Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Economic Value ◽  
Geographic Distance ◽  
Natural Populations ◽  
Fundamental Information ◽  
Betula Maximowicziana ◽  
Amova Analysis

SummaryBetula maximowicziana is a long-lived pioneer tree species in cool temperate forests that plays an important role in the forest ecosystem and has high economic value. Random amplified polymorphic DNA (RAPD) markers were used to evaluate the genetic variation of four natural populations of B. maximowicziana (three in central Honshu and the other in Hokkaido) to obtain fundamental information on this natural resource. Sixty-one reproductive amplified bands were obtained with 23 primers. Of these 61 bands, 22 were monomorphic and 39 were polymorphic. The level of genetic variation within each population may be very similar, because the population rankings according to number of polymorphic loci, Shannon’s indices and intra-population genetic variance revealed no definite patterns. Global analysis of AMOVA (analysis of molecular variance) showed that genetic variation among populations accounted for 15.6% of the total variation, with the remainder (84.4%) occurring within population. These results demonstrate that genetic differentiation among the four populations is moderate. Hierarchical AMOVA analysis showed that variation among regions (Hokkaido and central Honshu) accounted for 10.4% of the total genetic variation, suggesting that regional genetic differentiation is relatively high. Significant correlations between pairwise ΦPTvalues and geographic distance were detected, and results of both a neighbor-joining dendrogram based on pairwise ΦPTvalues, and principal coordinate analysis (PCO) based on a Euclidean metric revealed that the Furano population in Hokkaido was genetically different from the three populations in central Honshu. The data obtained in this study should have important implications for the conservation and management of regional genetic variation of B. maximowicziana.

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