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 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.

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

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 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.

scholarly journals Mixed-Mating Model of Reproduction Revealed in European Phytophthora cactorum by ddRADseq and Effector Gene Sequence Data

2021 ◽  
Vol 9 (2) ◽  
pp. 345
Author(s):  
Matěj Pánek ◽  
Ivana Střížková ◽  
Miloslav Zouhar ◽  
Tomáš Kudláček ◽  
Michal Tomšovský
Keyword(s):  
Sequence Data ◽  
Mixed Mating ◽  
Phytophthora Cactorum ◽  
Multiple Introductions ◽  
Effector Gene ◽  
Original Distribution ◽  
Sexual Recombination ◽  
Mixed Mating Model ◽  
Mating Model ◽  
F Statistics

A population study of Phytophthora cactorum was performed using ddRADseq sequence variation analysis completed by the analysis of effector genes—RXLR6, RXLR7 and SCR113. The population structure was described by F-statistics, heterozygosity, nucleotide diversity, number of private alleles, number of polymorphic sites, kinship coefficient and structure analysis. The population of P. cactorum in Europe seems to be structured into host-associated groups. The isolates from woody hosts are structured into four groups described previously, while isolates from strawberry form another group. The groups are diverse in effector gene composition and the frequency of outbreeding. When populations from strawberry were analysed, both asexual reproduction and occasional outbreeding confirmed by gene flow among distinct populations were detected. Therefore, distinct P. cactorum populations differ in the level of heterozygosity. The data support the theory of the mixed-mating model for P. cactorum, comprising frequent asexual behaviour and inbreeding alternating with occasional outbreeding. Because P. cactorum is not indigenous to Europe, such variability is probably caused by multiple introductions of different lineages from the area of its original distribution, and the different histories of sexual recombination and host adaptation of particular populations.

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 NONRANDOM MATING IN AN OPEN-POLLINATED MAIZE POPULATION

Genetics ◽  
1986 ◽  
Vol 112 (3) ◽  
pp. 669-680
Author(s):  
R Bijlsma ◽  
R W Allard ◽  
A L Kahler
Keyword(s):  
Zea Mays L ◽  
Marker Locus ◽  
Mixed Mating ◽  
Nonrandom Mating ◽  
Gametophytic Selection ◽  
Maize Population ◽  
Marker Loci ◽  
Different Populations ◽  
Mixed Mating Model ◽  
Mating Model

ABSTRACT Randomness of fertilization was studied in an open-pollinated population of maize (Zea mays L.) through allozyme assays of seedlings from open-pollinated seeds produced on both tasseled and detasseled plants. Mixed-mating-model estimates of the amount of outcrossing (t) were not significantly different from t = 1.00 for four enzyme loci (Adh1, Idh2, Got1 and Acp1), indicating that fertilizations were at random in the population. However, for loci Prx1 and Est4, estimates of t were significantly smaller than unity-0.80 and 0.70 for tasseled plants and 0.81 and 0.80 for detasseled plants. The excesses of homogametic fertilizations detected on the detasseled plants could not have been due to selffertilization, s = 1 - t, because the detasseled plants shed no pollen. Analyses of allelic frequencies in the pollen that produced seed on the detasseled plants established that different maternal plants sampled genetically different populations of pollen from the outcross pollen pool. It was suggested that the causes of the differential sampling were temporal variation in the pollen pool, and/or gametophytic selection, correlated with marker-locus genotype. Two-, three- and four-locus interactions among the marker loci were often statistically significant, indicating that the factors responsible for the nonrandom gametic unions observed in the maize population studied were complexly interactive.

Outcrossing in two faba bean cultivars under dryland conditions in Spain

1995 ◽  
Vol 75 (2) ◽  
pp. 441-443 ◽  
Author(s):  
M. J. Suso ◽  
J. I. Cubero ◽  
M. T. Moreno
Keyword(s):  
Faba Bean ◽  
Mediterranean Region ◽  
Mixed Mating ◽  
Isozyme Markers ◽  
Local Cultivar ◽  
Vicia Faba L ◽  
Outcrossing Rates ◽  
Mixed Mating Model ◽  
Mating Model

Field outcrossing rates were estimated for two faba bean (Vicia faba L.) cultivars in 3 yr in Spain using isozyme markers and the mixed mating model for the determination of single and multilocus rates. Out-crossing rates were stable during the years for the local cultivar and higher than previously thought for the Mediterranean region. Key words:Vicia faba, outcrossing rates, isozyme marker

scholarly journals EVOLUTION OF INTERACTIONS IN FAMILY-STRUCTURED POPULATIONS: MIXED MATING MODELS

Genetics ◽  
1980 ◽  
Vol 96 (1) ◽  
pp. 275-296
Author(s):  
Richard E Michod
Keyword(s):  
Mating System ◽  
Mating Systems ◽  
Random Mating ◽  
Additive Model ◽  
Multiplicative Model ◽  
Structured Populations ◽  
Mixed Mating ◽  
Genotypic Distribution ◽  
Individual Fitness ◽  
Recessive Genes

ABSTRACT The effect of inbreeding on sociality is studied theoretically for the evolution of interactions between siblings in certain mixed mating systems that give rise to inbreeding: sib with random mating and selfing with random mating. Two approaches are taken. First, specific models of altruism are studied for the various mating systems. In the case of the additive model, inbreeding facilitates the evolution of altruistic genes. Likewise, for the multiplicative model this is usually the case, as long as the costs of altruism are not too great. Second, the case of total altruism, in which the gene has zero individual fitness but increases the fitness of associates, is studied for a general fitness formulation. In this case, inbreeding often retards the ability of such genes to increase when rare, and the equilibrium frequency of those recessive genes that can increase is totally independent of the mating system and, consequently, of the amount of inbreeding. It appears from the results presented that inbreeding facilitates most forms of altruism, but retards extreme altruism. These results stem from the fact that inbreeding increases the within-family relatedness by increasing the between-family variance in allele frequency. In most cases this facilitates altruism. However, in the case of total altruism, only heterozygotes can pass on the altruistic allele, and inbreeding tends to decrease this heterozygote class. In either case, the important effect of inbreeding lies in altering the genotypic distribution of the interactions.

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