scholarly journals The role of breeding system and inbreeding depression in the maintenance of an outcrossing mating strategy inSilene virginica(Caryophyllaceae)

2001 ◽  
Vol 88 (11) ◽  
pp. 1953-1959 ◽  
Author(s):  
Michele R. Dudash ◽  
Charles B. Fenster
Keyword(s):  
Inbreeding Depression ◽  
Breeding System ◽  
Mating Strategy

scholarly journals Maternal effects alter the severity of inbreeding depression in the offspring

2016 ◽  
Vol 283 (1838) ◽  
pp. 20161023 ◽  
Author(s):  
Natalie Pilakouta ◽  
Per T. Smiseth
Keyword(s):  
Maternal Effects ◽  
Inbreeding Depression ◽  
Potential Role ◽  
Causal Effect ◽  
Natural Populations ◽  
Larval Survival ◽  
Burying Beetle ◽  
Nicrophorus Vespilloides ◽  
Selection For

A maternal effect is a causal influence of the maternal phenotype on the offspring phenotype over and above any direct effects of genes. There is abundant evidence that maternal effects can have a major impact on offspring fitness. Yet, no previous study has investigated the potential role of maternal effects in influencing the severity of inbreeding depression in the offspring. Inbreeding depression is a reduction in the fitness of inbred offspring relative to outbred offspring. Here, we tested whether maternal effects due to body size alter the magnitude of inbreeding depression in the burying beetle Nicrophorus vespilloides . We found that inbreeding depression in larval survival was more severe for offspring of large females than offspring of small females. This might be due to differences in how small and large females invest in an inbred brood because of their different prospects for future breeding opportunities. To our knowledge, this is the first evidence for a causal effect of the maternal phenotype on the severity of inbreeding depression in the offspring. In natural populations that are subject to inbreeding, maternal effects may drive variation in inbreeding depression and therefore contribute to variation in the strength and direction of selection for inbreeding avoidance.

scholarly journals Point estimation and graphical inference of marginal dominance for two viability loci controlling inbreeding depression

1997 ◽  
Vol 70 (2) ◽  
pp. 143-153 ◽  
Author(s):  
YONG-BI FU ◽  
DEBORAH CHARLESWORTH ◽  
GENE NAMKOONG
Keyword(s):  
Inbreeding Depression ◽  
Gene Action ◽  
Marker Locus ◽  
Point Estimation ◽  
Relative Role ◽  
Selfed Progeny ◽  
Deterministic Analysis ◽  
Partial Dominance ◽  
Segregation Ratios

A deterministic analysis is conducted to examine marginal dominance for two linked viability loci influencing inbreeding depression and its graphical inferences. Four estimators of marginal dominance are derived, assuming a biallelic marker locus completely linked to one of the viability loci, and the biases in expected estimates due to the other deleterious locus are discussed. Three conditions under which apparent partial dominance or underdominance could occur are found, i.e. when two multiplicative, partially recessive loci are linked in coupling phase and when two synergistic, highly overdominant loci are linked in coupling or repulsion phases. Expected frequencies of the three marker genotypes in selfed progeny are derived, considering two linkage phases, two types of marker locus position with respect to the viability loci, and the multiplicative and synergistic fitness models. Segregation ratios are generated for the marker locus linked to either two overdominant or partially recessive loci and plotted in gene action graphs to examine the robustness of the graphical inferences of gene action due to the presence of an additional linked viability locus. Under a multiplicative fitness model, the presence of an additional partially recessive or overdominant locus in the vicinity of the marker locus does not greatly affect the graphical inferences of the relative role of partially recessive or overdominant genes in expression of inbreeding depression. A marker linked to two synergistic, highly overdominant loci can behave as though linked to a partially recessive, partially dominant or underdominant locus, even with relatively weak synergism.

Avoidant strategy in insecure females

2009 ◽  
Vol 32 (1) ◽  
pp. 25-26 ◽  
Author(s):  
Bin-Bin Chen ◽  
Dan Li
Keyword(s):  
Middle Childhood ◽  
Early Experience ◽  
Mating Strategy ◽  
Growing Up ◽  
Short Term ◽  
Aggressive Environment ◽  
Avoidant Attachment

AbstractThis commentary cites evidence to argue that girls growing up in a competitive and aggressive environment are more likely to shift to avoidant attachment than to ambivalent attachment in middle childhood. These avoidant women are also more likely to favor a short-term mating strategy. The role of oxytocin (OT) and early experience in shaping an avoidant attachment in females is also discussed.

Influence of density and major histocompatibility genotype on sexual selection in a salmonid alternative mating strategy

2012 ◽  
Vol 69 (4) ◽  
pp. 670-680 ◽  
Author(s):  
Laura K. Weir ◽  
Jeffrey A. Hutchings ◽  
Daniel D. Heath
Keyword(s):  
Sexual Selection ◽  
Salmo Salar ◽  
Fertilization Success ◽  
Mating Strategy ◽  
Male Mating ◽  
Salmonid Fishes ◽  
Major Histocompatibility ◽  
Main Determinant ◽  
Alternative Mating Strategy

Various mechanisms of sexual selection can occur at both the whole organism and gamete levels. Fertilization success in salmonid fishes is largely determined by behavioural competition within and between “fighter” and “sneaker” male strategies, but is also influenced by interactions among gametes. We investigated the influence of density, fighter male presence, and major histocompatibility (MH) genotype on patterns of fertilization success in sneaker Atlantic salmon ( Salmo salar ). At low density and in the absence of fighter males, monopolization by single sneaker males occurred, suggesting that male–male competition was the main determinant of fertilization success. By contrast, at high density and (or) in the presence of fighter males, several sneakers succeeded in fertilizing eggs. Our study, the first to investigate the role of MH-mediated fertilization for a genetically based alternative male mating strategy, suggests that a larger proportion of eggs were fertilized by sneakers whose MH genotypes were more similar to those of the female than expected by chance. These findings highlight the importance of examining sexual selection under different competitive conditions.

Floral biology and late-acting self-incompatibility in Jacaranda racemosa (Bignoniaceae)

2006 ◽  
Vol 54 (3) ◽  
pp. 315 ◽  
Author(s):  
Nelson S. Bittencourt ◽  
João Semir
Keyword(s):  
Breeding System ◽  
Histological Analysis ◽  
Floral Biology ◽  
Self Incompatibility ◽  
Flower Visitation ◽  
Hand Pollination ◽  
Natural Pollination ◽  
Ovule Penetration ◽  
Incompatibility Barrier

Breeding-system studies have been conducted with 38 of the approximately800 species of Bignoniaceae, and self-incompatibility was found in 31 of these. In species for which the site of self-incompatibility barrier was studied, self-pollinated flowers consistently failed to develop into fruits, even though pollen tubes grew down to the ovary and penetrated most of the ovules. In this study, we have investigated the floral biology and the breeding system in Jacaranda racemosa Chamisso, with hand-pollination experiments and the histology of post-pollination events. Flower anthesis lasted 1–3 days, and although the frequency of flower visitation was extremely low, natural pollination seemed to be effected mainly by medium-sized bees. Because the conspicuous staminodium favours eventual pollination by small bees, a possible role of the staminodium in the increase of potential pollinators is suggested. Hand-pollinations indicated that J. racemosa is a self-sterile species. Histological analysis of post-pollination events indicated the occurrence of a kind of late-acting self-incompatibility in which the processes of ovule penetration, fertilisation and endosperm initiation were slower in selfed than in crossed pistils. Until the time of self-pollinated pistil abscission, no signs of endosperm malfunction or proembryo development were observed in selfed pistils. Therefore, inbreeding depression is an unlikely explanation for self-sterility in J. racemosa.

scholarly journals CORRELATED EVOLUTION OF MATING STRATEGY AND INBREEDING DEPRESSION WITHIN AND AMONG POPULATIONS OF THE HERMAPHRODITIC SNAILPHYSA ACUTA

Evolution ◽  
2009 ◽  
Vol 63 (11) ◽  
pp. 2790-2804 ◽  
Author(s):  
Juan S. Escobar ◽  
Benoît Facon ◽  
Philippe Jarne ◽  
Jérôme Goudet ◽  
Patrice David
Keyword(s):  
Inbreeding Depression ◽  
Mating Strategy ◽  
Correlated Evolution
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