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.

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.

scholarly journals Microsatellite analysis of the mating system of Bruguiera gymnorrhiza and Kandelia obovata

2018 ◽  
Vol 197 ◽  
pp. 06003
Author(s):  
Mohammad Basyuni ◽  
Shigeyuki Baba ◽  
Hirosuke Oku ◽  
Ridha Wati ◽  
Annisa Fitri
Keyword(s):  
Mating System ◽  
System Analysis ◽  
Genetic Relatedness ◽  
Mixed Mating ◽  
Bruguiera Gymnorrhiza ◽  
Mangrove Tree ◽  
Mixed Mating Model ◽  
Mating Model ◽  
Inbreeding Level ◽  
Cross Fertilization

Microsatellite loci were used for estimating mating system for three populations of B. gymnorrhiza and K. obovata (Rhizophoracea) in Okinawa, Japan. Mother trees and thirty offspring of individual samples representing the population of both species were genotyped at five microsatellites. The mating system was examined using two approaches: a mixed mating model of multilocus testing, implemented by MLTR program and outcrossing rate from the level of inbreeding. Mating system analysis showed multilocus outcrossing rates (tm) for both species was 0.850-1.000 and 0.780-0.938 respectively. By contrast, according to inbreeding level, tm was lower than MLRT: 0.495-1.028 and 0.480-0.612 of both species respectively. However, biparental inbreeding (tm- ts) was diverse from zero both species for all three populations, showing that cross-fertilization events may ensue between the relatives both species. This data as well means the genetic relatedness (r) for B. gymnorrhiza and K. obovata were 0.108±0.025 and 0.032±0.09 respectively. Average relatedness was below 0.25, the value for a half-sib relationship. These results suggest that postulation of a half-sib relationship among progeny of open-pollinated families is opposed for both mangrove tree species.

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 Life cycle expression of inbreeding depression in Eucalyptus regnans and inter-generational stability of its mixed mating system

2019 ◽  
Vol 124 (1) ◽  
pp. 179-187 ◽  
Author(s):  
A Rod Griffin ◽  
Brad M Potts ◽  
René E Vaillancourt ◽  
J Charles Bell
Keyword(s):  
Life Cycle ◽  
Mating System ◽  
Inbreeding Depression ◽  
Field Experiments ◽  
Natural Populations ◽  
Forest Tree ◽  
Mixed Mating ◽  
Mature Trees ◽  
Mixed Mating System ◽  
Eucalyptus Regnans

Abstract Background and Aims Many plants exhibit a mixed mating system. Published models suggest that this might be an evolutionarily stable rather than a transitional state despite the presence of inbreeding depression, but there is little empirical evidence. Through field experimentation, we studied the role of inbreeding depression in eliminating inbred progeny from the reproductive cohort of the forest tree Eucalyptus regnans, and demonstrate a stable mixed primary mating system over two successive generations. Methods Two field experiments were conducted using seed from natural populations. We sowed open-pollinated seeds to simulate a natural regeneration event and determined isozyme genotypes of dominant and suppressed individuals over 10 years. We also planted a mixture of open-pollinated, outcross and selfed families with common maternal parentage; monitored survival of cross types over 29 years; and determined the percentage of outcrosses in open-pollinated seed from a sample of reproductively mature trees using microsatellite analysis. Key Results Both experiments demonstrated progressive competitive elimination of inbred plants. By 29 years, the reproductive cohort in the planted experiment consisted only of outcrosses which produced seed which averaged 66 % outcrosses, similar to the estimate for the parental natural population (74 %). Conclusions Selective elimination of inbred genotypes during the intense intra-specific competition characteristic of the pre-reproductive phase of the life cycle of E. regnans results in a fully outcrossed reproductive population, in which self-fertility is comparable with that of its parental generation. The mixed mating system may be viewed as an unavoidable consequence of the species’ reproductive ecology, which includes the demonstrated effects of inbreeding depression, rather than a strategy which is actively favoured by natural selection.

Mating system of Racosperma auriculiforme in a seed production area in Zaire

1993 ◽  
Vol 71 (6) ◽  
pp. 779-785 ◽  
Author(s):  
P. Damase Khasa ◽  
William M. Cheliak ◽  
Jean Bousquet
Keyword(s):  
Mating System ◽  
Seed Production ◽  
Random Mating ◽  
Single Locus ◽  
Acacia Auriculiformis ◽  
Mixed Mating ◽  
Outcrossing Rates ◽  
Production Area ◽  
Mixed Mating Model ◽  
Mating Model

Analysis of the mating system of Racosperma auriculiforme (formerly Acacia auriculiformis) in a seed production area in Zaire was conducted using a mixed mating model at five polymorphic loci (Est-2, Est-3, G6p-dh, Nadhdh-2, Pgm-1). Single-locus estimates of outcrossing rate varied widely between 0.615 and 1.204 and were significantly heterogenous among and within the stands. Weighted means of single-locus estimates of outcrossing rates (ts) ranged from 0.859 to 1.032 while multilocus estimates of outcrossing rates (tm) ranged from 0.863 to 1.059. Comparisons between the single-locus estimates and the multilocus estimates of outcrossing rates indicated that most of the inbreeding detected was due to consanguineous (sibling) matings rather than selfing. Comparisons of observed and expected inbreeding coefficients indicated a general deficit of heterozygotes over the frequencies expected from random mating in the single stands and the pooled stands. Locus to locus variation in outcrossing rates suggested that violation of the mixed mating model might have occurred. Implications for seed production, collection, and distribution for reforestation are discussed. Key words: Acacia, mating system, Racosperma, seed production area, Zaire.

scholarly journals Estimation of Fagus sylvatica L mating system parameters in natural populations

1994 ◽  
Vol 51 (2) ◽  
pp. 163-173 ◽  
Author(s):  
D Merzeau ◽  
B Comps ◽  
B Thiébaut ◽  
J Letouzey
Keyword(s):  
Mating System ◽  
Fagus Sylvatica ◽  
Natural Populations ◽  
System Parameters ◽  
Fagus Sylvatica L

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.

MONTE CARLO STUDIES OF PLANT MATING SYSTEM ESTIMATION MODELS: THE ONE-POLLEN PARENT AND MIXED MATING MODELS

Genetics ◽  
1986 ◽  
Vol 112 (4) ◽  
pp. 927-945
Author(s):  
Daniel J Schoen ◽  
Michael T Clegg
Keyword(s):  
Monte Carlo ◽  
Mating System ◽  
Bootstrap Method ◽  
Pollen Parent ◽  
Mixed Mating ◽  
Plant Populations ◽  
System Parameters ◽  
Monte Carlo Studies ◽  
The One ◽  
Estimation Models

ABSTRACT Estimation of mating system parameters in plant populations typically employs family-structured samples of progeny genotypes. These estimation models postulate a mixture of self-fertilization and random outcrossing. One assumption of such models concerns the distribution of pollen genotypes among eggs within single maternal families. Previous applications of the mixed mating model to mating system estimation have assumed that pollen genotypes are sampled randomly from the total population in forming outcrossed progeny within families. In contrast, the one-pollen parent model assumes that outcrossed progeny within a family share a single-pollen parent genotype. Monte Carlo simulations of family-structured sampling were carried out to examine the consequences of violations of the different assumptions of the two models regarding the distribution of pollen genotypes among eggs. When these assumptions are violated, estimates of mating system parameters may be significantly different from their true values and may exhibit distributions which depart from normality. Monte Carlo methods were also used to examine the utility of the bootstrap resampling algorithm for estimating the variances of mating system parameters. The bootstrap method gives variance estimates that approximate empirically determined values. When applied to data from two plant populations which differ in pollen genotype distributions within families, the two estimation procedures exhibit the same behavior as that seen with the simulated data.

The mating system in natural populations of Thujaorientalis

1991 ◽  
Vol 21 (3) ◽  
pp. 333-339 ◽  
Author(s):  
Chang Yi Xie ◽  
Bruce P. Dancik ◽  
Francis C. Yeh
Keyword(s):  
Mating System ◽  
Expectation Maximization ◽  
Natural Populations ◽  
Expectation Maximization Algorithm ◽  
Outcrossing Rate ◽  
Significant Heterogeneity ◽  
System Parameters ◽  
Marker Loci ◽  
Self Fertilization ◽  
The Mean

EM (expectation–maximization) algorithm procedures were used to estimate mating-system parameters in four natural populations of Thujaorientalis L. from China using seven allozyme marker loci (Fest1, Idh1, Idh2, Mr, Pgi2, Skdh1, and 6Pg2). The mean single-locus outcrossing rate was 0.70 for the species, but estimates showed that there was significant heterogeneity among loci within populations. Multilocus estimates of the outcrossing rate showed that there was significant heterogeneity among populations and among trees within populations. The mean multilocus outcrossing rate (0.75) was higher than the outcrossing rate (0.63) observed in a closely related conifer, Thujaoccidentalis L., but lower than estimates that have been reported for most other conifers. Significant heterozygote deficiencies, relative to Hardy–Weinberg and mating-system equilibria, were observed in all filial populations. In contrast, the maternal populations conformed to Hardy–Weinberg and mating-system equilibria at most loci. Self-fertilization and other forms of inbreeding (e.g., sibling mating) within the sampled populations are important contributors to the low outcrossing estimates in this conifer.

The Mating System and Genetic Diversity of the Australian Arid Zone Mallee, Eucalyptus rameliana

1995 ◽  
Vol 43 (5) ◽  
pp. 461 ◽  
Author(s):  
JF Sampson ◽  
SD Hopper ◽  
SH James
Keyword(s):  
Genetic Diversity ◽  
Mating System ◽  
Arid Zone ◽  
Genetic Distances ◽  
Mixed Mating ◽  
Allozyme Diversity ◽  
Mixed Mating Model ◽  
Mating Model ◽  
Bird Migrations ◽  
The Impact

Estimates of parameters of the mixed mating model were made for three populations of the bird-pollinated arid zone eucalypt, Eucalyptus rameliana F. Muell. Levels of outcrossing ((t) over cap) varied significantly between populations from mixed mating with substantial selfing ((t) over cap = 0.54) to almost completely outcrossed ((t) over cap = 0.95). Comparison of single-locus and multilocus estimates suggested that the drop in outcrossing was due to increased self-pollination. The lowest outcrossing rate was attributed to the reduced ability of a population with low numbers of buds to attract bird pollinators. Outcrossing rates in E. rameliana are proposed to be a more direct reflection of pollination than estimates made for mass flowering, i.e. small-fruited eucalypts. The distribution of allozyme diversity in E. rameliana also appeared to reflect the impact of bird pollinators in promoting gene flow as well as the species capacity for outcrossing and introgression. Levels of diversity were comparable with other eucalypts, but the proportion of diversity between populations (GST = 9.2%) was only about half the mean for other eucalypts. Genetic distances between populations were low, but there was same significant differentiation of populations which was attributed to non-random bird migrations. The importance of bird pollination in the mating system and the distribution of genetic diversity in E. rameliana emphasises that enough habitat to support nomadic birds should be preserved in order to conserve this eucalypt species.

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