Lack of allozymic variation in disjunct Newfoundland populations of red pine (Pinusresinosa)

1991 ◽  
Vol 21 (4) ◽  
pp. 525-528 ◽  
Author(s):  
A. Mosseler ◽  
D. J. Innes ◽  
B. A. Roberts
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Cellulose Acetate ◽  
Gel Electrophoresis ◽  
Red Pine ◽  
Enzyme Electrophoresis ◽  
Isolated Populations ◽  
Putative Gene ◽  
Enzyme Gene ◽  
Enzyme Systems

Disjunct, geographically isolated populations of red pine (Pinusresinosa Ait.) on the island of Newfoundland were investigated by enzyme electrophoresis to determine if these populations were genetically distinct from a range-wide sample of mainland populations. Genetic variation at 23 putative gene loci from 12 enzyme systems was assayed by cellulose acetate gel electrophoresis. Each of the 96 trees sampled was monomorphic for all enzyme gene loci assayed, and no genetic differentiation between Newfoundland and mainland populations was detected. The striking lack of genetic variation at enzyme gene loci in red pine has been confirmed for the most isolated populations at the extreme northeastern margins of its range.

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.

Little genetic variation in the oil sardine, Sardinella longiceps Val., from the western coast of India

1994 ◽  
Vol 45 (2) ◽  
pp. 257 ◽  
Author(s):  
MR Menezes
Keyword(s):  
Genetic Variation ◽  
Gel Electrophoresis ◽  
Western Coast ◽  
Starch Gel Electrophoresis ◽  
Marine Fish Species ◽  
Average Heterozygosity ◽  
Enzyme Gene ◽  
Starch Gel ◽  
Sardinella Longiceps ◽  
Gene Variability

Enzyme gene variability in the oil sardine, Sardinella longiceps, from three localities along the western coast of India was studied by starch-gel electrophoresis. Out of 19 loci scored, no locus was polymorphic by the 95% criterion. Seven loci were polymorphic at the P=0.99 level. The average heterozygosity ranged from 0.6% to 0.9%. These values are very low compared with those of other marine fish species.

Isozyme Variation in Eucalyptus nitens and E. denticulata

1998 ◽  
Vol 46 (1) ◽  
pp. 35 ◽  
Author(s):  
Ian O. Cook ◽  
Pauline Y. Ladiges
Keyword(s):  
Genetic Variation ◽  
Morphological Characteristics ◽  
Geographic Range ◽  
The Other ◽  
Isozyme Variation ◽  
Eucalyptus Nitens ◽  
Isolated Populations ◽  
Single Population ◽  
Central Victoria ◽  
Enzyme Systems

Seed samples from 22 populations across the geographic range ofE. nitens (Deane & Maiden) Maiden s. str. andE. denticulata I.O. Cook & P.Y. Ladiges wereanalysed for isozyme variation and estimation of the genetic distance betweenthe two taxa. Analysis of 12 enzyme systems in 3 buffer systems revealed 12polymorphic and 5 monomorphic loci. The results confirm the distinctiveness ofE. nitens and E. denticulatapreviously reported for morphological characteristics. A single population ofthe related species E. quadrangulata Deane & Maidenwas distinct from, and more heterogeneous than, populations of the other two taxa. The results also show regional genetic variation withinE. nitens that correlates with observed differences inmorphology. Three races were identified: northern and central NSW; southern NSW and Mt Kay in eastern Victoria; Baw Baw Ranges and Central Highlands inVictoria. Geographically isolated populations, particularly from central andnorthern NSW, showed the least genetic variation. Variation was highest in anequivocal population from Mt Gregory, central Victoria, where the distributionof E. nitens overlaps with that ofE. denticulata.

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.

Structure et variabilité génétique de populations d'épinette noire (Piceamariana (Mill.) B.S.P.) dans la zone hémiarctique du Nouveau-Québec

1987 ◽  
Vol 17 (9) ◽  
pp. 1006-1012 ◽  
Author(s):  
Mireille Desponts ◽  
Jean-Pierre Simon
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Variability ◽  
Gel Electrophoresis ◽  
Black Spruce ◽  
Geographic Isolation ◽  
Marginal Populations ◽  
Isolated Populations ◽  
Subarctic Region ◽  
Enzyme Systems

The genetic structure of five populations of black spruce located at l'Eau Claire Lake, in the subarctic region of Nouveau-Québec, were analysed by acrylamide gel electrophoresis of seven enzyme systems. The analysis of 25 loci disclosed an average polymorphism of 0.80 and a level of heterozygosity of 0.351. Results indicate that there is no loss of genetic variability in these marginal populations that could be attributed to genetic drift. Data based on Wright's statistics indicate an excess of heterozygotes for most loci. Populations share the same alleles at most loci and are only slightly differentiated from each other (Fst = 0.06). Results suggest that gene flow between these isolated populations remains sufficiently high to override the effect of geographic isolation.

scholarly journals Genetic Variation in Turkish Red Pine (Pinus brutia Ten.) Seed Stands as Determined by RAPD Markers

2004 ◽  
Vol 53 (1-6) ◽  
pp. 169-175 ◽  
Author(s):  
G. Eren Kandedmir ◽  
I. Kandemir ◽  
Zeki Kaya
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Rapd Marker ◽  
Red Pine ◽  
Anthropogenic Factors ◽  
Pinus Brutia ◽  
Turkish Red Pine ◽  
The Impact ◽  
Seed Stand

SummaryTurkish red pine (Pinus brutia Ten.) is one of the important tree species in Turkey. The species has been heavily disturbed by anthropogenic factors and fire, making it important to understand the magnitude of the impact on genetic diversity of areas reserved for seed production. To explore the extent of genetic variation in Turkish red pine seed stands, a random amplified polymorphic DNA (RAPD) marker system was used in the study. The estimated genic diversity for seed stands was found to range from H =0.17 (P, %of polymorphic loci =%58.7) in Çameli-Göldağ to 0.29 (P =%81.7) in Bayramiç-Karaköy seed stand though the lowest polymorphism was observed in Fındıkpınarı seed stand (P =55.8%). The total gene diversity was calculated as HT=0.34, in Turkish red pine. About 65% of the total diversity was within seed stands. No distinct pattern of genetic diversity was found according to the geography, elevation or breeding zones. The highest genetic differentiation was found in the Western Mediterranean geographic region, however, within population genetic diversity was found to be similar among different geographic regions (HS=0.22-0.24). GSTvalue calculated was high (0.35) indicating that genetic differentiation among the studied seed stands was substantial. Dendrogram constructed with genetic distance data did not yield a firm pattern with respect to geography, elevation and breeding zones. In fact, the most of the clusters in the dendrogram had very low bootstrap values, suggesting that the clusters could be refined if more populations and markers are included in the future studies. The implication of the results with respect to in situ conservation of genetic resources of the species was discussed.

Genetic diversity and genetic differentiation in Echinococcus granulosus (Batsch, 1786) from domestic and sylvatic hosts on the mainland of Australia

Parasitology ◽  
1990 ◽  
Vol 101 (2) ◽  
pp. 283-289 ◽  
Author(s):  
A. J. Lymbery ◽  
R. C. A. Thompson ◽  
R. P. Hobbs
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Echinococcus Granulosus ◽  
Enzyme Electrophoresis ◽  
Rostellar Hook ◽  
Eastern Australia

Enzyme electrophoresis was used to examine genetic variation within and between populations of Echinococcus granulosus from domestic and sylvatic hosts in western and eastern Australia. Substantial genetic diversity was found within all populations. There was no evidence, however, of genetic differentiation between populations from different hosts or geographic areas. When isolates were grouped into previously described domestic or sylvatic strains on the basis of rostellar hook morphology, most (94%) of the genetic variation occurred within, rather than between strains. These results conflict with the currently accepted theory of separate domestic and sylvatic strains of E. granulosus on the mainland of Australia.

STRUCTURE OF GENETIC VARIATION WITHIN AND BETWEEN POPULATIONS OF MYCOPHAGOUS DROSOPHILA

Genetics ◽  
1983 ◽  
Vol 104 (1) ◽  
pp. 81-94
Author(s):  
Robert C Lacy
Keyword(s):  
New York ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Gel Electrophoresis ◽  
Site Fidelity ◽  
Adaptive Divergence ◽  
Gene Frequencies ◽  
Polymorphic Loci ◽  
Diversifying Selection ◽  
Study Sites

ABSTRACT Patterns of genetic variation within and between populations of five species of mycophagous Drosophila were examined by gel electrophoresis of several polymorphic loci. Populations of the five species could not be shown to be subdivided into sympatric host-adapted races. Statistically significant, but small, between-host differences in gene frequencies were observed at three of 15 loci. Mean gene frequencies at all loci were similar in New York and Tennessee, and, with one exception, relatively little genetic differentiation was observed among study sites within those two regions. Gene frequencies generally were stable over several years of collecting as well. The unpredictable nature of the fungal hosts may preclude the site fidelity and continuity of diversifying selection necessary for adaptive divergence of populations.

scholarly journals Population genetic variation analysis of bitter gourd wilt caused by Fusarium oxysporum f. sp. momordicae in China using inter simple sequence repeats (ISSR) molecular markers

2021 ◽  
Author(s):  
Rui Zang ◽  
Ying Zhao ◽  
Kangdi Guo ◽  
Kunqi Hong ◽  
Huijun Xi ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Fusarium Oxysporum ◽  
Diversity Index ◽  
Gene Diversity ◽  
Pcr Amplification ◽  
Bitter Gourd ◽  
Diseased Plant ◽  
Variation Analysis ◽  
Group I

AbstractBitter gourd wilt caused by Fusarium oxysporum f. sp. momordicae (FOM) is a devastating crop disease in China. A total of 173 isolates characteristic of typical Fusarium oxysporum with abundant microconidia and macroconidia on white or ruby colonies were obtained from diseased plant tissues. BLASTn analysis of the rDNA-ITS of the isolates showed 99% identity with F. oxysporum species. Among the tested isolates, three were infectious toward tower gourd and five were pathogenic to bottle gourd. However, all of the isolates were pathogenic to bitter gourd. For genetic differences analysis, 40 ISSR primers were screened and 11 primers were used for ISSR-PCR amplification. In total, 127 loci were detected, of which 76 were polymorphic at a rate of 59.84%. POPGENE analysis showed that Nei’s gene diversity index (H) and Shannon’s information index (I) were 0.09 and 0.15, respectively, which indicated that the genetic diversity of the 173 isolates was low. The coefficient of gene differentiation (Gst = 0.33 > 0.15) indicated that genetic differentiation was mainly among populations. The strength of gene flow (Nm = 1.01 > 1.0) was weak, indicating that the population differentiation caused by gene drift was blocked to some degree. The dendrogram based on ISSR markers showed that the nine geographical populations were clustered into two groups at the threshold of genetic similarity coefficient of 0.96. The Shandong and Henan populations were clustered into Group I, while the Guangdong, Hainan, Guangxi, Fujian, Jiangxi, and Hubei populations constituted Group II. Results of the genetic variation analysis showed that the Hunan and Guangxi populations had the highest degree of genetic differentiation, while the Hubei population had the lowest genetic differentiation. Our findings enrich the knowledge of the genetic variation characteristics of FOM populations with the goal of developing effective disease-management programs and resistance breeding programs.

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