Allozyme differentiation among populations, stands, and cohorts in Monterey pine

1986 ◽  
Vol 16 (6) ◽  
pp. 1155-1164 ◽  
Author(s):  
Martha E. Plessas ◽  
Steven H. Strauss
Keyword(s):  
Gene Diversity ◽  
Random Mating ◽  
Natural Populations ◽  
Morphological Characters ◽  
Allele Frequencies ◽  
Monterey Pine ◽  
Fixation Indices ◽  
The One ◽  
Old Trees ◽  
Allozyme Loci

Four- to six-year-old trees were sampled from 9 to 10 stands in each of three natural populations of Monterey pine (Pinusradiata D. Don) and studied for genetic diversity at 37 allozyme loci. Among loci, Nei's gene diversity ranged from 73 to 100% within stands, 0 to 10% between stands within populations, and 0 to 27% between populations; average values were 94.9, 1.6, and 3.5%, respectively. F-statistic analyses (B. S. Weir and C. C. Cockerham. 1984. Evolution (Lawrence, Kans.), 38: 1358–1370) indicated higher levels of stand and population differentiation than did Nei's diversity statistics: 2.6 ± 0.7 and 6.2 ± 2.6%, respectively. Homozygotes were significantly in excess relative to expectations under random mating (FIS = 0.065). Most loci showed highly significant variation of allele frequencies among populations; Nei's genetic distance averaged 0.014. Genetic and geographic distances among stands were correlated only at Año Nuevo. Introgression of genes from knobcone pine (Pinusattenuata Lemm.) was evident in the one stand where the species were sympatric. Contrary to inferences from growth and morphological characters, allozyme frequencies and other biochemical characters suggest that the Año Nuevo population diverged prior to Cambria and Monterey. Differentiation among three cohorts was studied at 10 loci. Allele frequencies varied nonsignificantly between cohorts; mean fixation indices, however, decreased monotonically with cohort age, from 0.081 in embryos to 0.038 in 5-year-old trees to −0.119 in 14- to 17-year-old trees. Selection for the more outbred progeny was the outcome of stand development.

Estimation of mating system parameters in two Italian natural populations of Fagussylvatica

1996 ◽  
Vol 26 (7) ◽  
pp. 1187-1192 ◽  
Author(s):  
Patrizia Rossi ◽  
Giovanni Giuseppe Vendramin ◽  
Raffaello Giannini
Keyword(s):  
Mating System ◽  
Natural Populations ◽  
Female Parent ◽  
European Beech ◽  
Allele Frequencies ◽  
Mixed Mating ◽  
System Parameters ◽  
Fixation Indices ◽  
Mixed Mating Model ◽  
Allozyme Loci

Mating system parameters were estimated in two Italian natural populations of European beech (Fagussylvatica L.) using a mixed mating model and considering seven allozyme loci (Idh-A, Lap-A, Mdh-B, Pgd-A, Pgd-B, Pgd-C, Skd-A). High values of multilocus estimates of the outcrossing rate were found in both populations, ranging from 94 to 98%. Comparison of single- and multi-locus estimates of outcrossing rates seems to indicate the presence of consanguineous matings, probably because the populations are substructured. This hypothesis seems to be confirmed by the presence of a heterogeneity of the pollen allele frequencies across female parent trees and by the significant coefficient of the regression of pollen allele frequencies on ovule genotype. Variation in the fixation indices in different life-cycle phases was observed, indicating possible presence of selective processes between seed set and sexual maturity. Possible explanations of these results are presented.

Variation in leaf characteristics among provenances of Eucalyptus camaldulensis Dehn. grown in Zambia

1971 ◽  
Vol 19 (2) ◽  
pp. 237
Author(s):  
J Burley ◽  
PJ Wood ◽  
AS Hans
Keyword(s):  
Principal Component Analysis ◽  
Leaf Shape ◽  
Natural Populations ◽  
Eucalyptus Camaldulensis ◽  
Principal Component ◽  
Morphological Characters ◽  
Leaf Length ◽  
Maximum Temperature ◽  
Ecotypic Variation ◽  
Old Trees

Eight morphological characters of leaves were examined in 2-year-old trees of 25 provenances of Eucalyptus camaldulensis Dehn, grown in a replicated trial in Zambia. Provenances differed significantly in leaf length and width, base angle, and oil gland density but significant effects were attributed to trees within provenances. Leaf curvature also varied between provenances, trees, and branches. The tip angle and the number of veins did not vary significantly. Leaf length and oil gland density were related to maximum temperature at seed source rather than to latitude but the reverse occurred for leaf width. Significant amounts of variation were explained by a linear combination of temperature and latitude but not by longitude, altitude, or rainfall. Information on seven traits was combined in principal component analysis in which the first component (a measure of leaf shape) accounted for 36% of total observed variation while the second (weighted largely on leaf length) accounted for 26%. Mapping of both univariate and multivariate results indicated that there are two major ecotypes and gave some evidence of clinal and ecotypic variation within them. The conclusions support those of other workers both in natural populations in Australia and in exotic populations elsewhere.

HORDEIN VARIATION IN WILD (HORDEUM SPONTANEUM) AND CULTIVATED (H. VULGARE) BARLEY

1979 ◽  
Vol 21 (3) ◽  
pp. 391-404 ◽  
Author(s):  
Hans Doll ◽  
A. H. D. Brown
Keyword(s):  
Linkage Disequilibrium ◽  
Wild Species ◽  
Storage Protein ◽  
Natural Populations ◽  
Hordeum Spontaneum ◽  
Allele Frequencies ◽  
Evolutionary Processes ◽  
Highly Correlated ◽  
The Individual ◽  
Allozyme Loci

The storage protein hordein contains two major groups of polypeptides which are highly polymorphic in barley, and in its evolutionary progenitor Hordeum spontaneum Koch. Crosses between the two species showed that the complex electrophoretic phenotypes within the two groups of polypeptides are governed by codominant alleles at two corresponding loci, Hor-1 and Hor-2, which are moderately linked (11% ± 2). In natural populations of the wild species, the two complex hordein loci were much more polymorphic than the allozyme loci. Furthermore, the variation at these two loci was highly correlated so that individuals differ from one another at both loci much more frequently than expected from the allele frequencies at the individual loci. Considerable hordein variation was also present in Composite Cross XXI, and there was evidence of reassortment of patterns by the seventeenth generation. Thus the complex hordein loci, with their extreme diversity and linkage disequilibrium, are ideal markers for monitoring evolutionary processes in both natural, or composite cross populations.

scholarly journals Genetic Structure of Natural Populations of Wild Sunflowers (Helianthus annuus L.) in Australia

1986 ◽  
Vol 39 (3) ◽  
pp. 255 ◽  
Author(s):  
PJ Dry ◽  
JJ Burdon
Keyword(s):  
Genetic Structure ◽  
Gene Diversity ◽  
New South ◽  
Geographic Distance ◽  
Natural Populations ◽  
Wild Populations ◽  
South Wales ◽  
Fixation Indices ◽  
O 19 ◽  
Isozyme Diversity

The genetic structure of 11 wild populations of H. annuus occurring in New South Wales and Queensland was determined by isozyme analysis. Considerable isozyme diversity was found among loci within and between populations, with three to five alleles being identified at each of 10 loci. Mean levels of heterozygosity ranged from o� 19 to O� 38 and gene diversity values from 0�29 to O� 52. In all populations Wright's fixation indices were positive (0�09-0� 51) suggesting a degree of inbreeding. Differences in the level of genetic differentiation between populations were not correlated with geographic distance. Indeed, notable genetic diversity was detected between six sites occurring within a 2-km radius of Gunnedah, N.S.W., where the genetic distance relationships were D = 0�13 � 0'08, the same as those between popUlations throughout the region.

scholarly journals Linkage Disequilibrium Between Allozymes in Natural Populations of Lodgepole Pine

Genetics ◽  
1987 ◽  
Vol 115 (2) ◽  
pp. 341-352
Author(s):  
B K Epperson ◽  
R W Allard
Keyword(s):  
Linkage Disequilibrium ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Random Mating ◽  
Natural Populations ◽  
Population Substructure ◽  
Population Subdivision ◽  
Chi Square ◽  
Pairwise Linkage Disequilibrium ◽  
Allozyme Loci

ABSTRACT Pairwise linkage disequilibrium values (D) were estimated for 14 allozyme loci in two natural populations of lodgepole pine (Pinus contorta ssp. latifolia). Maternal multilocus genotypes were inferred from samples of (haploid) megagametophytic seed-endosperms. Coupling/repulsion double heterozygotes were distinguished for closely linked pairs of loci. Assays of seven of the loci in seed embryos allowed estimates of D for these loci in the outcross pollen pool (estimates of outcrossing rates indicate no significant departures from random mating in either population). No disequilibrium was observed between unlinked loci in either maternal genotypes or outcross pollen. However, significant disequilibrium was observed within and between gametes for some allelic combinations of four tightly linked loci; the assumption of random association of gamete types within individuals is thus invalid for some loci in lodgepole pine. Possible causes of the observed D were examined using the noncentrality parameter of the general noncentral chi square distribution. We concluded, from estimates of population size, linkage and measurements of population substructure, that neither drift nor population subdivision was responsible for the significant values of D which were observed and that epistatic selection was the most likely cause of the disequilibrium observed.

scholarly journals NULL ALLELE FREQUENCIES AT ALLOZYME LOCI IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1981 ◽  
Vol 99 (1) ◽  
pp. 151-156
Author(s):  
Charles H Langley ◽  
Robert A Voelker ◽  
Andrew J Leigh Brown ◽  
Seido Ohnishi ◽  
Barbara Dickson ◽  
...  
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Null Allele ◽  
Natural Populations ◽  
Allele Frequencies ◽  
Null Alleles ◽  
Carolina Population ◽  
The Mean ◽  
Allozyme Loci ◽  
Two Populations

ABSTRACT We have sampled a London population of Drosophila melanogaster for null alleles at twenty-five allozyme loci. The same loci and biochemical techniques were used as in our previous survey of a North Carolina population (Voelker et al. 1980). This second survey is completely concordant with the first. No nulls were detected among the five X-linked loci. The mean frequency of nulls at the twenty autosomal loci was 0.0023. Although there is significant interlocus heterogeneity, the two populations appear to have the same frequencies at each locus. This suggests that null alleles at these allozyme loci are in mutation-selection balance, and we estimate the average heterozygous effect of an allozyme null to be 0.0015. Consideration of allozyme null-allele frequencies, the effects of allozyme null alleles on viability and fertility and the generally greater amount of genetic variability at allozyme loci determined by electrophoresis lead us to doubt the validity of generalizing from allozyme data to the whole genome.

HETEROSIS AT ALLOZYME LOCI UNDER INBREEDING AND CROSSBREEDING IN PINUS ATTENUATA

Genetics ◽  
1986 ◽  
Vol 113 (1) ◽  
pp. 115-134
Author(s):  
Steven H Strauss
Keyword(s):  
Slow Growth ◽  
Natural Populations ◽  
Identity By Descent ◽  
Cone Production ◽  
Isozyme Loci ◽  
Total Proportion ◽  
Outcrossing Species ◽  
Old Trees ◽  
Allozyme Loci ◽  
Relationship Of

ABSTRACT The dependence of heterosis at isozyme loci on inbreeding and crossbreeding was studied in 10-yr-old trees of knobcone pine (Pinus attenuata Lemm.). Heterozygosity was determined at 24 polymorphic isozyme loci and related to the rate of vegetative growth and cone production. The inbreds, created by selfpollination, had 46% of the heterozygosity of their mothers; the crossbreds, created by interpopulation crossing, had 155% of the heterozygosity of their mothers. Within the crossbreds, heterozygosity was positively correlated with trunk growth, but negatively correlated with cone production. Results in the crossbreds, however, were strongly influenced by a few individuals that showed unusually slow growth, high reproduction and low heterozygosity. Without those individuals, there was no relationship of heterozygosity to either growth or reproduction.—Within the inbreds, heterozygosity was positively correlated with both trunk growth and cone production. Each locus that was heterozygous in the mothers was calculated to mark about 3% of the genome for identity by descent in the inbred progeny; the total proportion of the genome marked was between 10 and 11%. Using these estimates to relate heterozygosity to the inbreeding coefficient (F) gave estimates of inbreeding depression per unit of F that fell within the range of published values for conifers. The strength of heterosis found among the inbreds suggests that single-locus or multilocus overdominance should be exceedingly difficult to detect in natural populations of predominantly outcrossing species

Evidence for natural interspecific hybridization between the Australian bass (Macquaria novemaculeata) and estuary perch (M. colonorum)

1999 ◽  
Vol 50 (7) ◽  
pp. 661 ◽  
Author(s):  
Dean R. Jerry ◽  
Tarmo A. Raadik ◽  
Stuart C. Cairns ◽  
Peter R. Baverstock
Keyword(s):  
Species Identification ◽  
Interspecific Hybridization ◽  
Interspecific Hybrids ◽  
Natural Populations ◽  
Morphological Characters ◽  
Morphometric Study ◽  
Gradient Gel Electrophoresis ◽  
Breeding Programmes ◽  
Temperature Gradient Gel Electrophoresis ◽  
Allozyme Loci

Australian bass (Macquaria novemaculeata) and estuary perch (M. colonorum) are very similar in their morphology, use of habitat and geographical distribution. Following the capture from four Victorian rivers of specimens possessing species-diagnostic attributes intermediate to the two taxa, an allozyme electrophoresis and morphometric study was undertaken to investigate the possibility that these individuals were the results of interspecific hybridization. Two allozyme loci were found to be useful in species identification and were used to confirm that the individuals in question were indeed interspecific hybrids. The presence of hybrids was further supported by univariate and multivariate analysis of morphological characters. Temperature-gradient gel electrophoresis on mtDNA control- region fragments demonstrated that where interspecific hybrids were identified, the maternal parent species was M. novemaculeata. The demonstration that M. novemaculeata and M. colonorum can hybridize in natural populations emphasizes the importance of correct species identification in breeding programmes to prevent the liberation of large numbers of interspecific hybrids.

scholarly journals INVERSIONS FAIL TO ACCOUNT FOR ALLOZYME CLINES

Genetics ◽  
1978 ◽  
Vol 88 (3) ◽  
pp. 515-527
Author(s):  
R A Voelker ◽  
C Clark Cockerham ◽  
F M Johnson ◽  
H E Schaffer ◽  
Terumi Mukai ◽  
...  
Keyword(s):  
United States ◽  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Allele Frequencies ◽  
Eastern United States ◽  
Allozyme Loci ◽  
And Inversion

ABSTRACT Allozyme and inversion data from natural populations of Drosophila melanogaster from the eastern United States were analyzed to determine whether the clines at allozyme loci are due to nonrandom associations with common cosmopolitan inversions. All inversions show strong clines. Clines were large and significant for half of the eight allozyme loci. An analysis of the contribution of inversions to clines of allozyme genes revealed three outcomes: the inversion cline (1) enhanced the allozyme cline, but was only partly responsible, (2) reduced the allozyme cline, and (3) had no effect. The allozyme clines were mainly determined by the pattern of allele frequencies within the chromosomal arrangements. Consequently, it was concluded that allozyme clines would exist in the absence of inversion clines.

scholarly journals Inferring Linkage Disequilibrium Between a Polymorphic Marker Locus and a Trait Locus in Natural Populations

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 457-467 ◽  
Author(s):  
Z W Luo ◽  
S H Tao ◽  
Z-B Zeng
Keyword(s):  
Linkage Disequilibrium ◽  
Allele Frequency ◽  
Random Mating ◽  
Natural Populations ◽  
Polymorphic Marker ◽  
Marker Locus ◽  
Model Parameters ◽  
Phenotypic Variance ◽  
Wide Range ◽  
Trait Locus

Abstract Three approaches are proposed in this study for detecting or estimating linkage disequilibrium between a polymorphic marker locus and a locus affecting quantitative genetic variation using the sample from random mating populations. It is shown that the disequilibrium over a wide range of circumstances may be detected with a power of 80% by using phenotypic records and marker genotypes of a few hundred individuals. Comparison of ANOVA and regression methods in this article to the transmission disequilibrium test (TDT) shows that, given the genetic variance explained by the trait locus, the power of TDT depends on the trait allele frequency, whereas the power of ANOVA and regression analyses is relatively independent from the allelic frequency. The TDT method is more powerful when the trait allele frequency is low, but much less powerful when it is high. The likelihood analysis provides reliable estimation of the model parameters when the QTL variance is at least 10% of the phenotypic variance and the sample size of a few hundred is used. Potential use of these estimates in mapping the trait locus is also discussed.

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