Selection against inbreds in early life-cycle phases in Pinus leucodermis Ant.

Morgante, Michèle; Vendramin, G. G.; Rossi, P.; Olivieri, A. M.

doi:10.1038/hdy.1993.89

Cited by 37 publications

(24 citation statements)

References 14 publications

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“…There seems to be no strong selection against inbred progeny because the adult sample also had an excess of homozygotes. In other studies, a decrease of F-values has been reported with increasing age of the analysed ontogenetic stages (Morgante et al, 1993). Another factor that might have contributed to the high values of F in Paracou is the Wahlund effect.…”

Section: Heterozygositymentioning

confidence: 96%

Limited pollen dispersal and biparental inbreeding in Symphonia globulifera in French Guiana

Деген

Bandou²,

Caron

2004

Heredity

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In this paper, we report a study of the mating system and gene flow of Symphonia globulifera, a hermaphroditic, mainly birdpollinated tree species with a large geographic distribution in the tropical Americas and Africa. Using three microsatellites, we analysed 534 seeds of 28 open pollinated families and 164 adults at the experimental site 'Paracou' in French Guiana. We observed, compared to other tropical tree species, relatively high values for the effective number of alleles. Significant spatial genetic structure was detected, with trees at distances up to 150 m more genetically similar than expected at random. We estimated parameters of the mating system and gene flow by using the mixed mating model and the TwoGener approach. The estimated multilocus outcrossing rate, t m , was 0.920. A significant level of biparental inbreeding and a high proportion of full-sibs were estimated for the 28 seed arrays. We estimated mean pollen dispersal distances between 27 and 53 m according to the dispersal models used. Although the adult population density of S. globulifera in Paracou was relatively high, the joint estimation of pollen dispersal and density of reproductive trees gave effective density estimates of 1.6 and 1.3 trees/ha. The parameters of the mating system and gene flow are discussed in the context of spatial genetic and demographic structures, flowering phenology and pollinator composition and behaviour.

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Section: Heterozygositymentioning

confidence: 96%

Limited pollen dispersal and biparental inbreeding in Symphonia globulifera in French Guiana

Деген

Bandou²,

Caron

2004

Heredity

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“…I), though only for the three trinucleotide loci this determined a significant departure from Hardy-Weinberg equilibrium, either within population or in the global sample. Homozygote excess has been so far shown in conifers mostly in juveniles [17], and it is possible that the type of tissue we have used for this study (seedlings or pools of megagametophytes) shows the same type of departure from equilibrium. However, only EATC1G02 showed distortion at the population level in 3 populations out of 4.…”

Section: Diversity Parameters and Global F St Values Are Shown Inmentioning

confidence: 99%

Population genetics of Norway spruce (Picea abiesKarst.) at regional scale: sensitivity of different microsatellite motif classes in detecting differentiation

2006

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-Four populations of Norway spruce (Picea abies Karst.) were screened using nine nuclear microsatellite markers (three trinucleotides and six dinucleotides) and four chloroplast markers (all mononucleotides). Marker classes were compared for their variability, mutation rate and ability to detect differentiation between stands. Dinucleotide markers proved to be the most variable group and chloroplast stretches the least variable, with differences in mutation rate between the former and the latter spanning over two orders of magnitude. Variability correlated to the number of repeats but not to the absolute length of the microsatellite region. The different marker classes were combined with two different measures of genetic distance in order to investigate the performance of markers and evolutionary models for the study of genetic variation in natural populations of Norway spruce. Weir and Cockeram's F ST generally performed better in this clear-cut, four-population model study. Chloroplast haplotypes turned out to be the most sensitive marker system, being able to differentiate populations and to detect differences in genetic variability between sub-regions.conifers / SSR / divergence / statistical testing / genetic distance Résumé -Génétique des populations d'épicéa (Picea abies Karst.) à l'échelle régionale : sensibilité de différent motifs microsatellites dans la détection de la différenciation. Quatre populations d'épicéa (Picea abies Karst.) ont été analysées avec neuf marqueurs microsatellite nucléaires (trois trinucléotidiques et six dinucléotidiques) et quatre marqueurs chloroplastiques (tous mononucléotidiques). La variabilité, le taux de mutation et la performance dans la détection de la différentiation entre sites de ces classes de marqueurs ont été comparées. Les marqueurs dinucléotidiques ont montré la plus forte variabilité, et les marqueurs chloroplastiques la plus faible, avec une différence en taux de mutation d'un facteur cent entre les deux classes. La variabilité est corrélé avec le nombre de répétions mais n'est pas corrélé avec la taille de la répétition. Les différentes classes des marqueurs ont été combinées avec deux mesures de distance génétique pour analyser les effets du choix du marqueur et du model évolutif sur l'étude de la variabilité génétique des populations naturelles d'épicéa. Le F ST de Weir et Cockeram a produit en général les meilleurs résultats dans cette simple étude sur quatre populations. Les haplotypes chloroplastiques ont montré la plus grande efficacité, permettant de distinguer les régions et les populations à l'intérieur des régions.conifères / SSR / divergence / test statistique / distance génétique

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“…However, two sources of bias could affect our estimation: (a) in spite of high exclusion probabilities, exclusion analysis has low power when the number of potential parents in the population is high [12]; and (b) selfs generated by parent trees outside the plot were not considered. In Pinus species, selection against inbreeds is expected to be extensive at the seed stage ( [24] and references within) whereas it has only been shown in some species to occur shortly after germination (Pinus leucodermis [33], Pinus sylvestris [34]). In maritime pine, most lethal or sublethal alleles are probably eliminated during seed formation and germination as well as during the first growing season.…”

Section: Discussionmentioning

confidence: 99%

Selfing and sibship structure in a two-cohort stand of maritime pine (Pinus pinaster Ait.) using nuclear SSR markers

González‐Martínez

Gerber²,

Cervera

et al. 2003

Ann. For. Sci.

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-The genetic relatedness between pairs of trees was analyzed in an adult stand of maritime pine with abundant advanced natural regeneration using three highly polymorphic microsatellites (EP > 90%). Only five possible self-pollinated offspring were found, thus meaning a maximum selfing rate based on dispersed progeny of 3.8%. Likelihood ratios were used to detect sib relationships in both mature trees and natural regeneration. The percentage of half-sib and full-sib links in the adult trees was 19.09% and 1.82%, respectively, thus indicating a low level of genetic relatedness due to sib relationships (» 3%). Similar results were obtained for the natural regeneration but with a higher percentage of full-sibs (2.37%) and a greater family size. A high amount of pollen gene flow from outside the plot is suggested to explain the low genetic relatedness found. Collection of seedlots in this stand seems adequate as a low level of inbreeding is expected.

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Selection against inbreds in early life-cycle phases in Pinus leucodermis Ant.

Cited by 37 publications

References 14 publications

Limited pollen dispersal and biparental inbreeding in Symphonia globulifera in French Guiana

Limited pollen dispersal and biparental inbreeding in Symphonia globulifera in French Guiana

Population genetics of Norway spruce (Picea abiesKarst.) at regional scale: sensitivity of different microsatellite motif classes in detecting differentiation

Selfing and sibship structure in a two-cohort stand of maritime pine (Pinus pinaster Ait.) using nuclear SSR markers

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