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.

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.

scholarly journals Demography and mating system shape the genome-wide impact of purifying selection in Arabis alpina

2017 ◽  
Author(s):  
Benjamin Laenen ◽  
Andrew Tedder ◽  
Michael D. Nowak ◽  
Per Toräng ◽  
Jörg Wunder ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Mating System ◽  
Purifying Selection ◽  
Mixed Mating ◽  
Genome Wide ◽  
Outcrossing Rates ◽  
Arabis Alpina ◽  
Whole Genome Resequencing ◽  
Evolutionary Consequences ◽  
The Impact

Plant mating systems have profound effects on levels and structuring of genetic variation, and can affect the impact of natural selection. While theory predicts that intermediate outcrossing rates may allow plants to prevent accumulation of deleterious alleles, few studies have empirically tested this prediction using genomic data. Here, we study the effect of mating system on purifying selection by conducting population genomic analyses on whole-genome resequencing data from 38 European individuals of the arctic-alpine crucifer Arabis alpina. We find that outcrossing and mixed-mating populations maintain genetic diversity at similar levels, whereas highly self-fertilizing Scandinavian A. alpina show a strong reduction in genetic diversity, most likely as a result of a postglacial colonization bottleneck. We further find evidence for accumulation of genetic load in highly self-fertilizing populations, whereas the genome-wide impact of purifying selection does not differ greatly between mixed-mating and outcrossing populations. Our results demonstrate that intermediate levels of outcrossing may allow efficient selection against harmful alleles whereas demographic effects can be important for relaxed purifying selection in highly selfing populations. Thus, both mating system and demography shape the impact of purifying selection on genomic variation in A. alpina. These results are important for an improved understanding of the evolutionary consequences of mating system variation and the maintenance of mixed-mating strategies.SignificanceIntermediate outcrossing rates are theoretically predicted to maintain effective selection against harmful alleles, but few studies have empirically tested this prediction using genomic data. We used whole-genome resequencing data from alpine rock-cress to study how genetic variation and purifying selection vary with mating system. We find that populations with intermediate outcrossing rates have similar levels of genetic diversity as outcrossing populations, and that purifying selection against harmful alleles is efficient in mixed-mating populations. In contrast, self-fertilizing populations from Scandinavia have strongly reduced genetic diversity, and accumulate harmful mutations, likely as a result of demographic effects of postglacial colonization. Our results suggest that mixed-mating populations can avoid the negative evolutionary consequences of high self-fertilization rates.

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 Demography and mating system shape the genome-wide impact of purifying selection in Arabis alpina

2018 ◽  
Vol 115 (4) ◽  
pp. 816-821 ◽  
Author(s):  
Benjamin Laenen ◽  
Andrew Tedder ◽  
Michael D. Nowak ◽  
Per Toräng ◽  
Jörg Wunder ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Mating System ◽  
Purifying Selection ◽  
Mating Strategies ◽  
Genomic Variation ◽  
The Arctic ◽  
Mixed Mating ◽  
Genome Wide ◽  
Arabis Alpina ◽  
The Impact

Plant mating systems have profound effects on levels and structuring of genetic variation and can affect the impact of natural selection. Although theory predicts that intermediate outcrossing rates may allow plants to prevent accumulation of deleterious alleles, few studies have empirically tested this prediction using genomic data. Here, we study the effect of mating system on purifying selection by conducting population-genomic analyses on whole-genome resequencing data from 38 European individuals of the arctic-alpine crucifer Arabis alpina. We find that outcrossing and mixed-mating populations maintain genetic diversity at similar levels, whereas highly self-fertilizing Scandinavian A. alpina show a strong reduction in genetic diversity, most likely as a result of a postglacial colonization bottleneck. We further find evidence for accumulation of genetic load in highly self-fertilizing populations, whereas the genome-wide impact of purifying selection does not differ greatly between mixed-mating and outcrossing populations. Our results demonstrate that intermediate levels of outcrossing may allow efficient selection against harmful alleles, whereas demographic effects can be important for relaxed purifying selection in highly selfing populations. Thus, mating system and demography shape the impact of purifying selection on genomic variation in A. alpina. These results are important for an improved understanding of the evolutionary consequences of mating system variation and the maintenance of mixed-mating strategies.

scholarly journals THE EFFECTIVE PROPORTION OF SELF-FERTILIZATION WITH CONSANGUINEOUS MATINGS IN INBRED POPULATIONS

Genetics ◽  
1984 ◽  
Vol 106 (1) ◽  
pp. 139-152
Author(s):  
Kermit Ritland
Keyword(s):  
Mixed Mating ◽  
Selfing Rate ◽  
Genotypic Distribution ◽  
Self Fertilization ◽  
Allelic Segregation ◽  
Mixed Mating Model ◽  
Mating Model ◽  
Inbred Populations ◽  
Biased Estimates ◽  
Independent Parameters

ABSTRACT Allelic segregation at a single locus among offspring derived from matings, including those between inbred relatives, is a combination of two patterns, corresponding to self-fertilization and random outcrossing. The proportion of effective self-fertilization is termed the "effective selfing rate," and it is specified with identity coefficients. The description of the offspring genotypic distribution for a population with mating among relatives requires a set of three independent parameters of genetic and mating structure. One such set is the inbreeding coefficient of parents, the coefficient of kinship between mates and the effective selfing rate. The model used to derive the effective selfing rate distinguishes between the effective selfing rates of inbred vs. outbred parents; the mixed mating model does not distinguish between these two rates. As a result, the mixed mating model usually gives biased estimates of effective selfing, if there is mating among inbred relatives. The procedure for estimation of effective selfing, based upon progeny array data distributed according to the "effective selfing model," is presented, and an example is given.

scholarly journals Variation in reproductive effort, genetic diversity and mating systems across Posidonia australis seagrass meadows in Western Australia

AoB Plants ◽  
2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Elizabeth A Sinclair ◽  
Jane M Edgeloe ◽  
Janet M Anthony ◽  
John Statton ◽  
Martin F Breed ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Mating System ◽  
Western Australia ◽  
Reproductive Effort ◽  
Genetic Data ◽  
Fruit Production ◽  
Mixed Mating ◽  
Mixed Mating System ◽  
Shark Bay ◽  
Range Edge

Abstract Populations at the edges of their geographical range tend to have lower genetic diversity, smaller effective population sizes and limited connectivity relative to centre of range populations. Range edge populations are also likely to be better adapted to more extreme conditions for future survival and resilience in warming environments. However, they may also be most at risk of extinction from changing climate. We compare reproductive and genetic data of the temperate seagrass, Posidonia australis on the west coast of Australia. Measures of reproductive effort (flowering and fruit production and seed to ovule ratios) and estimates of genetic diversity and mating patterns (nuclear microsatellite DNA loci) were used to assess sexual reproduction in northern range edge (low latitude, elevated salinities, Shark Bay World Heritage Site) and centre of range (mid-latitude, oceanic salinity, Perth metropolitan waters) meadows in Western Australia. Flower and fruit production were highly variable among meadows and there was no significant relationship between seed to ovule ratio and clonal diversity. However, Shark Bay meadows were two orders of magnitude less fecund than those in Perth metropolitan waters. Shark Bay meadows were characterized by significantly lower levels of genetic diversity and a mixed mating system relative to meadows in Perth metropolitan waters, which had high genetic diversity and a completely outcrossed mating system. The combination of reproductive and genetic data showed overall lower sexual productivity in Shark Bay meadows relative to Perth metropolitan waters. The mixed mating system is likely driven by a combination of local environmental conditions and pollen limitation. These results indicate that seagrass restoration in Shark Bay may benefit from sourcing plant material from multiple reproductive meadows to increase outcrossed pollen availability and seed production for natural recruitment.

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.

Male Gametophytic Selection Against a Deleterious Allele in a Mixed Mating Model

Hereditas ◽  
2004 ◽  
Vol 120 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Christian Damgaard ◽  
Bernt Guldbrandtsen ◽  
Freddy B. Christiansen
Keyword(s):  
Mixed Mating ◽  
Deleterious Allele ◽  
Gametophytic Selection ◽  
Mixed Mating Model ◽  
Mating Model

scholarly journals Outcrossing rate of Couratari multiflora (J.Smith) Eyma (Lecythidaceae), a low-density tropical tree species from a central Amazonian rainforest

2011 ◽  
Vol 41 (1) ◽  
pp. 153-162 ◽  
Author(s):  
Nadja Lepsch-Cunha ◽  
Paulo Yoshio Kageyama ◽  
Roland Vencovsky ◽  
Henrique E. M. Nascimento
Keyword(s):  
Tree Species ◽  
Random Mating ◽  
Small Sample ◽  
Outcrossing Rate ◽  
Reproductive Phenology ◽  
Mixed Mating ◽  
Long Distance ◽  
Sample Number ◽  
Mixed Mating Model ◽  
Mating Model

A multilocus mixed-mating model was used to evaluate the mating system of a population of Couratari multiflora, an emergent tree species found in low densities (1 individual/10 ha) in lowland forests of central Amazonia. We surveyed and observed phenologically 41 trees in an area of 400 ha. From these, only four mother trees were analyzed here because few of them set fruits, which also suffered high predation. No difference was observed between the population multilocus outcrossing rate (t mp = 0.953 ± 0.040) and the average single locus rate (t sp = 0.968 ± 0.132). The four mother trees were highly outcrossed (t m ~ 1). Two out of five loci showed departures from the Hardy-Weinberg Equilibrium (HWE) expectations, and the same results occurred with the mixed-mating model. Besides the low number of trees analyzed, the proportion of loci in HWE suggests random mating in the population. However, the pollen pool was heterogeneous among families, probably due to both the small sample number and the flowering of trees at different times of the flowering season. Reproductive phenology of the population and the results presented here suggest, at least for part of the population, a long-distance pollen movement, around 1,000 m.

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