The Evolution of Infidelity in Socially Monogamous Passerines: Neglected Components of Direct and Indirect Selection

2007 ◽  
Vol 169 (2) ◽  
pp. 274
Author(s):  
Griffith

2011 ◽  
Vol 279 (1734) ◽  
pp. 1700-1708 ◽  
Author(s):  
Jane M. Reid ◽  
Rebecca J. Sardell

One specific hypothesis explaining the evolution of extra-pair reproduction (EPR) by socially monogamous females is that EPR is under indirect selection because extra-pair offspring (EPO) sired by extra-pair males have higher additive genetic value for fitness than the within-pair offspring (WPO) a female would have produced had she solely mated with her socially paired male. This hypothesis has not been explicitly tested by comparing additive genetic value between EPO and the WPO they replaced. We show that the difference in additive genetic breeding value (BV) between EPO and the WPO they replaced is proportional to the genetic covariance between offspring fitness and male net paternity gain through EPR, and estimate this covariance with respect to offspring recruitment in free-living song sparrows ( Melospiza melodia ). Recruitment and net paternity gain showed non-zero additive genetic variance and heritability, and negative genetic covariance. Opposite to prediction, EPO therefore had lower BV for recruitment than the WPO they replaced. We thereby demonstrate an explicit quantitative genetic approach to testing the hypothesis that EPR allows polyandrous females to increase offspring additive genetic value, and suggest that there may be weak indirect selection against female EPR through reduced additive genetic value for recruitment of EPO versus WPO in song sparrows.





HortScience ◽  
1990 ◽  
Vol 25 (11) ◽  
pp. 1357F-1358
Author(s):  
Yiran Yu ◽  
James Harding ◽  
Thomas Byrne

Genetic components of variance and heritability of flowering time were estimated for five generations of the Davis Populationof Gerbera hybrids, Composite, Estimates of narrow-sense heritability averaged 0.50 and broad-sense heritability averaged 0.77 using the NCII design. Narrow-sense heritability was also estimated with two models of parent-offspring regression, resulting in average heritability of 0.49 and 0.51. Estimates of components of variance indicated that the major genetic effect controlling flowering time is additive. However, the dominance component accounted for 28% of the total variance; the environmental component was only 23%. Flowering time is negatively correlated with cut-flower yield. The phenotypic coefficient was –0.34; genetic correlations were –0.47 when estimated from the NCII design, and –0.72 when estimated from the parent-off-spring method. A practical model was constructed to assess the efficiency of indirect selection for cut-flower yield using flowering time as a marker trait. The advantages of indirect selection accruing from increased population size and reduced generation time are discussed.



Crop Science ◽  
1993 ◽  
Vol 33 (6) ◽  
pp. 1127-1131 ◽  
Author(s):  
E. J. Oosterom ◽  
S. Ceccarelli


The Auk ◽  
2005 ◽  
Vol 122 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Alexander M. Mills

AbstractProtandry, the earlier arrival of males than of females on breeding areas, occurs in many taxa, including many migratory birds. Numerous hypotheses have been generated to explain protandry. Using bird-banding records, I show that protogyny, the earlier migration of females, frequently occurs in the autumn, though it is less universal and less dramatic than spring protandry. In one species, it occurs in both hatch-year and adult birds. When (1) spring and autumn, (2) departures and arrivals, and (3) breeding and wintering ground conditions are considered, hypotheses generated only to explain spring protandry can be more thoroughly evaluated. Using that approach, the most parsimonious explanation of differential migration between the sexes explains earlier male arrival in spring and later male departure in autumn through either (1) indirect selection operating on intrasexual male competition for territories or (2) direct selection operating on intersexual relations requiring males to be present on breeding territories when females are present. In autumn-protogynous species, males may ”play chicken,” balancing the benefits of remaining longer than females and protecting territories for subsequent years against the costs of remaining in the north under deteriorating conditions and delaying the acquisition of a good winter territory.Protogynie et migration automnale: Est-ce que les mâles ”jouent les dégonflés”?



Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1510
Author(s):  
Samuel Henrique Kamphorst ◽  
Gabriel Moreno Bernardo Gonçalves ◽  
Antônio Teixeira do Amaral Júnior ◽  
Valter Jário de Lima ◽  
Kátia Fabiane Medeiros Schmitt ◽  
...  

The identification of traits associated with drought tolerance in popcorn is a contribution to support selection of superior plants under soil water deficit. The objective of this study was to choose morphological traits and the leaf greenness index, measured on different dates, to estimate grain yield (GY) and popping expansion (PE), evaluated in a set of 20 popcorn lines with different genealogies, estimated by multiple regression models. The variables were divided into three groups: morpho-agronomic traits—100-grain weight (GW), prolificacy (PR), tassel length (TL), number of tassel branches, anthesis-silking interval, leaf angle (FA) and leaf rolling (FB); variables related to the intensity of leaf greenness during the grain-filling period, at the leaf level, measured by a portable chlorophyll meter (SPAD) and at the canopy level, calculated as the normalized difference vegetation index (NDVI). The inbred lines were cultivated under two water conditions: well-watered (WW), maintained at field capacity, and water stress (WS), for which irrigation was stopped before male flowering. The traits GY (55%) and PE (28%) were most affected by water restriction. Among the morpho-agronomic traits, GW and PR were markedly reduced (>10%). Under dry conditions, the FA in relation to the plant stalk tended to be wider, the FB curvature greater and leaf senescence accelerated (>15% at 22 days after male flowering). The use of multiple regression for the selection of predictive traits proved to be a useful tool for the identification of groups of adequate traits to efficiently predict the economically most important features of popcorn (GY and PE). The SPAD index measured 17 days after male flowering proved useful to select indirectly for GY, while, among the morphological traits, TL stood out for the same purpose. Of all traits, PR was most strongly related with PE under WS, indicating its use in breeding programs. The exploitation of these traits by indirect selection is expected to induce increments in GY and PE.



Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2249-2258 ◽  
Author(s):  
Mark M Iles ◽  
Kevin Walters ◽  
Chris Cannings

AbstractIt is well known that an allele causing increased recombination is expected to proliferate as a result of genetic drift in a finite population undergoing selection, without requiring other mechanisms. This is supported by recent simulations apparently demonstrating that, in small populations, drift is more important than epistasis in increasing recombination, with this effect disappearing in larger finite populations. However, recent experimental evidence finds a greater advantage for recombination in larger populations. These results are reconciled by demonstrating through simulation without epistasis that for m loci recombination has an appreciable selective advantage over a range of population sizes (am, bm). bm increases steadily with m while am remains fairly static. Thus, however large the finite population, if selection acts on sufficiently many loci, an allele that increases recombination is selected for. We show that as selection acts on our finite population, recombination increases the variance in expected log fitness, causing indirect selection on a recombination-modifying locus. This effect is enhanced in those populations with more loci because the variance in phenotypic fitnesses in relation to the possible range will be smaller. Thus fixation of a particular haplotype is less likely to occur, increasing the advantage of recombination.



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