Genetic variation in trembling aspen in Ontario based on isozyme studies

1987 ◽  
Vol 17 (9) ◽  
pp. 1134-1138 ◽  
Author(s):  
Jung O. Hyun ◽  
Om P. Rajora ◽  
Louis Zsuffa

Isoenzyme studies were conducted on root tips of 200 Populustremuloides clones selected from eight geographic regions (populations) along north–south and east–west transects in Ontario. Starch gel electrophoresis was used to assay crude enzyme extracts from young root rips of rooted suckers obtained from the clones sampled. A total of 15 isozyme loci coding for eight different enzyme systems were resolved. The mean of total gene diversity was 0.252. An average of 79% of the loci were polymorphic in any one population, with an average of 2.7 alleles per locus. More than 90% of the genetic variability could be attributed to within-population differentiation. A deficiency of observed heterozygotes was calculated for all populations studied. The fixation index averaged 0.462. The genetic distance estimates among populations had an overall mean of 0.103. There was no correlation between genetic and geographic distances. Results of this study suggest this species in its Ontario range is genetically variable and moderately differentiated.

Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Om P. Rajora ◽  
Louis Zsuffa

Horizontal starch gel electrophoresis of enzymes was used to study genetic divergence among Populus deltoides Marsh. (section Aigeiros Duby, Salicaceae), P. nigra L. (section Aigeiros), and P. maximowiczii Henry (section Tacamahaca Spach.) at 37 to 40 allozyme loci coding for 12 enzyme systems in root tips. These three Populus species were genetically distinct from each other. Populus deltoides, P. nigra, and P. maximowiczii had mutually exclusive alleles at two loci, and each of these species had unique alleles at many loci. Certain allozyme loci were detected only in one or two of these species. Frequency distributions of allozyme loci were bimodal with respect to genetic identity for comparisons between any two species. The mean genetic distance was 0.36 ± 0.10 between P. deltoides and P. nigra, 0.39 ± 0.09 between P. deltoides and P. maximowiczii, and 0.34 ± 0.10 between P. nigra and P. maximowiczii. The enzyme electrophoretic evidence indicated a monophyletic origin of the three Populus species.Key words: poplars, genetic identity and divergence, allozymes, molecular evolution, phylogenetics.


2016 ◽  
Vol 42 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Katarzyna Buczkowska ◽  
Alina Bączkiewicz ◽  
Patrycja Gonera

Abstract Calypogeia azurea, a widespread, subboreal-montane liverwort species, is one of a few representatives of the Calypogeia genus that are characterized by the occurrence of blue oil bodies. The aim of the study was to investigate the genetic variation and population structure of C. azurea originating from different parts of its distribution range (Europe and North America). Plants of C. azurea were compared with C. peruviana, another Calypogeia species with blue oil bodies. In general, 339 gametophytes from 15 populations of C. azurea were examined. Total gene diversity (HT) estimated on the basis of nine isozyme loci of C. azurea at the species level was 0.201. The mean Nei’s genetic distance between European populations was equal to 0.083, whereas the mean genetic distance between populations originating from Europe and North America was 0.413. The analysis of molecular variance (AMOVA) showed that 69% of C. azurea genetic variation was distributed among regions (Europe and North America), 15% - among populations within regions, and 16% - within populations. Our study revealed that C. azurea showed genetic diversity within its geographic distribution. All examined samples classified as C. azurea differed in respect of isozyme patterns from C. peruviana.


1989 ◽  
Vol 67 (9) ◽  
pp. 2600-2607 ◽  
Author(s):  
Adrian Leuchtmann ◽  
Keith Clay

Isozyme variation of 291 isolates of Atkinsonella hypoxylon (Clavicipitaceae, tribe Balansieae) from 24 populations of its four known host grasses (Danthonia compressa, Danthonia sericea, Danthonia spicata, and Stipa leucotricha) was examined using starch gel electrophoresis. In total, there were 20 distinct multilocus genotypes. Eleven out of 13 enzyme loci (84.6%) exhibited more than one allele (mean 2.8) per locus. Nei's total gene diversity (HT) within all isolates was 0.229. Between isolate samples from S. leucotricha and the three Danthonia hosts, Nei's genetic identity (I) ranged from 0.21 to 0.31 and among isolate samples from the three Danthonia species I ranged from 0.65 to 0.88, with isolates from D. spicata and D. compressa being most similar. Variation of A. hypoxylon occurred both within and among populations of D. spicata and D. compressa, where up to 53 isolates were sampled per host population. In contrast, all 20 isolates from S. leucotricha were identical, as were all 6 from D. sericea. A few isolates from D. spicata exhibited the same, unusual multilocus genotype with unique alleles at six different loci. The occurrence of several multilocus genotypes in isolates from the same ascostroma and the 1:1 segregation of genotypes among ascospores from a single ascus indicated gene exchange among sexually reproducing individuals, consistent with a heterothallic mating system for A. hypoxylon.


1996 ◽  
Vol 74 (7) ◽  
pp. 1138-1146 ◽  
Author(s):  
Brett G. Purdy ◽  
Randall J. Bayer

As part of an analysis of genetic diversity in endemic taxa of the Athabasca sand dunes in northern Saskatchewan, Canada, genetic variation was examined by starch gel electrophoresis in six populations of the endemic Achillea millefolium ssp. megacephala, and 13 populations of the closely related widespread taxon, A. millefolium ssp. lanulosa. Endemic populations had more alleles per locus, a higher percentage of polymorphic loci, and greater genetic diversity than did populations of the widespread taxon. At polymorphic loci, total gene diversity was comparable in both taxa, although within-population gene diversity was higher in the endemic taxon. Population differentiation (GST) was considerably lower in ssp. megacephala than in ssp. lanulosa, although GST values were reduced when the parameter was calculated separately for geographic subdivisions of the widespread taxon. Our results differ from previous studies in which the endemic is typically depauperate of genetic variation relative to related widespread species. We suggest that obligate sexual reproduction and the absence of long-term asexual reproduction may be one of a number of factors that help populations of ssp. megacephala maintain higher levels of genetic variation on the Athabasca sand dunes. Keywords: genetic variation, endemic, rare species, Athabasca sand dunes, Achillea millefolium.


Genetics ◽  
1984 ◽  
Vol 108 (3) ◽  
pp. 669-679
Author(s):  
J M Martinez-Zapater ◽  
Jose L Oliver

ABSTRACT The genetic control of eight isozyme loci revealed by starch gel electrophoresis was studied through the analysis of three progenies derived from four tetraploid cultivars of Solanum tuberosum (groups Andigena and Tuberosum). Duplicate gene expression was found in seven (Got-A, Got-B, Pgd-C, Pgi-B, Pgm-A, Pgm-B and Pox-C) isozyme loci. In another isozyme gene (Adh-A), the parental genotypes were not adequate to distinguish between a monogenic or a digenic model of genetic control. Tetrasomic inheritance was demonstrated in four (Got-A, Got-B, Pgd-C and Pgi-B) isozyme loci. In the remaining duplicate genes, the parental genotypes precluded discrimination between disomic or tetrasomic models. Tetrasomic segregations of the chromosomal type were generally found; however, the isozyme phenotypes shown by three descendants from selfing cv. Katahdin indicate the occurrence of chromatid segregations, although aneuploidy cannot be ruled out. Either autoploidy or amphidiploidy with lack of chromosome differentiation between the two diploid ancestors can account for the existence of tetrasomic inheritance in the common potato.


1997 ◽  
Vol 45 (1) ◽  
pp. 1-8
Author(s):  
Gabriel Schiller ◽  
Leonid Korol

Isoenzyme variants withinCupressus sempervirensL. planted in Israel have been identified using starch gel electrophoresis of enzymes extracted from the megagametophytic and perisperm seed tissue. Single-tree cone collection from 493 trees growing in 27 populations at holy sites and in plantations planted at the end of the 19th and the beginning of the 20th century in the country was done in 1986–1987. In 1994 viable seeds were available from only 267; of them, 140 trees were phenotypically identified as var.pyramidalisand 67 as being of var.horizontalis; the other 60 trees were not identified phenotypically. The results gained show that in the plantedC. sempervirensL. under investigation 11 (47.8%) out of the 23 gene loci in 13 enzyme systems analyzed were polymorphic; they contain a relatively high gene diversity of 0.479. The genetic distance between the two varieties planted in Israel is 0.007. Differences in allele frequencies between the two varieties occurred only in 5 loci, viz., IDH2PGI2, MDH3, PGM1, and ACO1.


1960 ◽  
Vol 54 (3) ◽  
pp. 321-328 ◽  
Author(s):  
G. C. Ashton

1. The serum β-globulin phenotype of 141 bulls located at Cattle Breeding Centres in England and Wales was determined by starch-gel electrophoresis.2. The distribution of the contemporary comparison values of these bulls with respect to β-globulin type was investigated. The great majority of the bulls were βAA, βAD, or βDD with very few βAE and βDE and no βEE types.3. The contemporary comparison values for 130 bulls of the three types βAA, βAD and βDD each fell into a normal distribution. The mean and its standard error and the standard deviation of the mean and its standard error were calculated for each of the three curves. The mean contemporary comparison value for the βAA bulls was + 12·2 ± 5·4 gal., for the βAD bulls + 26·8 ± 5·4 gal., and for the βDD bulls + 38·2 ± 5·5 gal. The βAA and βDD means were significantly different (P < 0·01).4. The pooled contemporary comparison values of the βAA, βAD and βDD bulls did not give a normal distribution curve, neither did the contemporary comparison values for a sample of 1028 bulls quoted by the Milk Marketing Board. However, when the contemporary comparison values of the βAA, βAD and βDD groups were superimposed around the same mean, the ensuing distribution was normal.5. It is concluded that the β-globulin locus is concerned in the genetic control of milk yield. The estimated mean genetic value of βD over βA is approximately + 50 gal. This is about one-sixth of the total genetic variation in milk yield in the major milk breeds.6. The distribution of butterfat percentages with respect to β-globulin phenotype in four Ayrshire and one Friesian herds was investigated. No difference between the mean first lactation butterfat percentage of the βAA, βAD, and βDD cows in each herd was found. There was an indication (not significant) that the mean butterfat percentage of the βAE and βDE cows in three of the four Ayrshire herds studied was higher than the mean of the other groups.


1992 ◽  
Vol 22 (10) ◽  
pp. 1504-1509 ◽  
Author(s):  
Stephanie A. Foré ◽  
R. James Hickey ◽  
Sheldon I. Guttman ◽  
John L. Vankat

Genetic data were collected for five developmentally based cohorts of Acersaccharum Marsh in a large southwestern Ohio nature preserve. A minimum of 48 individuals were sampled from each of the following cohorts: embryos, 1st-year seedlings, and three diameter at breast height classes (≤ 2, 15–25, and ≥ 40 cm). Genotypes at eight loci were inferred from phenotypic enzyme patterns of seven enzymes extracted from cambial tissue and resolved by starch gel electrophoresis. Allelic data were subdivided by cohort and statistically compared. There was no significant difference in observed heterozygosity among the cohorts. Nei's gene diversity statistics, Nei's unbiased genetic distance, and χ2 analyses of allele and genotype frequency heterogeneity indicated that there was little genetic differentiation among cohorts. The observed differentiation resulted from allele and genotype frequency differences between seedlings and other cohorts.


Author(s):  
Iain F. Wilson ◽  
Elizabeth M. Gosling ◽  
William Tapper

Eight samples of Littorina tenebrosa and L. saxatilis (Mollusca: Gastropoda) from Ireland and Britain, including pairs of each form from two locations in Ireland, were screened for genetic variation at 12 polymorphic enzyme loci using starch gel electrophoresis. Levels of polymorphism and heterozygosity were similar in L. tenebrosa and L. saxatilis, apart from a sample of L. tenebrosa from Britain which was less polymorphic than the Irish samples. No alleles were found to be unique to either form. Phylogenetic analysis using UPGMA showed that L. saxatilis and L. tenebrosa populations clustered as a monophyletic group. Nevertheless, the mean genetic distance between parapatric populations of L. saxatilis and L. tenebrosa (D=0.076) was similar to the mean for allopatric populations of either species (D=0.080). This indicates that there is a barrier to gene flow between the two forms Despite this, L. tenebrosa does not merit specific status since populations of this snail do not cluster as a distinct group, separate from L. saxatilis populations.


1994 ◽  
Vol 119 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Paul D. Mangum ◽  
Ellen B. Peffley

Horizontal starch gel electrophoresis was used to study the inheritance of isozyme phenotypes of four enzyme systems [alcohol dehydrogenase (ADH), 6-phosphogluconate dehydrogenase (6-PGDH), phosphoglucomutase (PGM), and shikimate dehydrogenase (SKDH)] in Allium fistulosum L. by monitoring segregations in backcross and F2 progeny. Segregation for most of the polymorphisms fit the expected Mendelian ratios as tested by the chi-square statistic. Three new isozyme loci were defined for onion. Two loci were found for 6-PGDH. Locus one was dimeric with two alleles, and locus two was monomorphic. SKDH was monomeric with two alleles.


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