Polymorphism due to selection of varying direction

Haldane, J. B. S.; Jayakar, S. D.

doi:10.1007/bf02986143

Cited by 436 publications

(332 citation statements)

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“…Under such heterogeneous environments, genetic polymorphism can be maintained if there is a habitat-genotype interaction in selection differentials (Haldane & Jayakar, 1963). In addition to this environmental heterogeneity, there is some evidence that there is a temporal heterogeneity for pollinator availability.…”

Section: Discussionmentioning

confidence: 99%

“…However, others have argued that various circumstances may maintain heritable variation in these traits by a mutation-selection balance (Lande, 1976), by antagonistic pleiotropy leading to genetic trade-offs (Rose, 1982;Falconer, 1989) or by selection varying in time and space (Haldane & Jayakar, 1963). The few studies of fitness traits of plants that have been published show that while some characters display moderate heritable variation, many have little or no detectable additive component (Arthur et al, 1973, and references therein;Mitchell-Olds, 1986;Mazer, 1987;Biere, 1991a,b;Dorn & Mitchell-Olds, 1991;Schwaegerle & Levin, 1991).…”

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confidence: 99%

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The quantitative genetics of floral characters in Mimulus guttatus

1994

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We examined the quantitative genetics of 20 floral traits in Mimulus guttatus including flowering time, autofertility, flower size, the spatial arrangement of flower parts, pollen and ovule production and seed number and size. A six by six diallel crossing design including selfs was performed in the glasshouse between plants derived from one population of M. guttatus from California. All characters with the exception of pollen number showed significant amounts of additive genetic variance indicating a potential to respond to selection. A principal components analysis revealed that some variation in many characters could be explained by general flower size. However, most characters still displayed heritable variation after the flower size effect was removed by analysis of covariance. Families showed considerable variation in the ability to self in glasshouse conditions. Only a weak relationship between autofertility and herkogamy was detected, suggesting that an unidentified mechanism was responsible for differences in selfing ability. Pollen quality and ovule production were also strongly heritable, suggesting the potential for gender specialization of plants but no trade-off between male and female function could be detected. Inbreeding depression was evident in flower size and pollen and ovule production. It is postulated that the heritable variation observed is maintained in this population through disruptive selection on autofertility in response to seasonal variation in the onset of spring drought and pollinator availability.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

The quantitative genetics of floral characters in Mimulus guttatus

1994

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“…In crosses between higher mortality strains the.heterozygote tended to be more resistant than either parent. This may contribute to the relatively constant mortalities throughout the year (Haldane and Jayakar 1963), as a dominance architecture is suitable for the maintenance of a uniformly high fitness in the population.…”

Section: Discussionmentioning

confidence: 99%

The Genetic Architecture of Resistance to Desiccation in Populations of Drosophila melanogaster and D. simulans

Ja¹,

Pa²

1974

Aust. Jnl. Of Bio. Sci.

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Populations of D. melanogaster and D. simulans from Melbourne, Vic., and Brisbane, Qld, were regularly sampled for resistance to desiccation. D. melanogaster was more resistant than D. simulans and females of each species were more resistant than males for both populations.The resistance observed for the D. melanogaster population from Melbourne and for the populations of both species from Brisbane remained fairly constant throughout a yearly cycle. However, the resistance of the D. simulans population from Melbourne was greatest during the warmest months and became progressively less as the temperature decreased. For this D. simulans population percentage mortality was correlated with mean temperature and temperature fluctuation of the Melbourne environment. No other correlation was found for any other population comparison.Laboratory populations, derived from founders of each area and kept at constant temperatures of 15, 20 and 25°C, provided results that agreed with the field data. The level of resistance of the D. simulans population from Melbourne appeared to be related to the environmental temperature of maintenance but the other populations maintained fairly uniform resistance levels over a number of generations.Diallel cross techniques indicate that the genetic architectures for resistance to desiccation of the Melbourne D. melanogaster population and of both species from Brisbane are similar, with additive, dominance and interaction effects being observed. Desiccation resistance for D. simulans from Melbourne is almost entirely additive, however. This result is discussed in relation to the field and laboratory data.

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“…This suggestion has been challenged by Creed (1975) who claims that their model does not result in a stable equilibrium and that heterozygote advantage must be present at some stage. On the other hand, Haldane and Jayakar (1963) point out that a polymorphism can be maintained by selection in opposite directions in a situation where the opposing selective forces are large, and Hedrick (1973) has shown that, in a situation analagous to that of A. bipunctata in Berlin, cyclic environmental variation can maintain a stable polymorphism. Lusis (1961) suggested that the greater changes in body temperature experienced by the melanic morphs as a result of their more rapid heating and cooling may account for the winter mortality found by Timoféeff-Ressovsky.…”

Section: The Nature Of the Disadvantage Of The Melanic Morphs (I) Selmentioning

confidence: 99%

Selection against the melanic morphs of Adalia bipunctata (two-spot ladybird): A review and some new data

Muggleton

1978

Heredity

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SUMMARYWork on the nature of the factors selecting against the melanie morphs of Adalia bipunetata is reviewed, New data are presented showing that there is normally one generation per year in Great Britain and that the cyclical changes in morph frequency observed in Berlin may not occur in Great Britain.The roles of migration and selective predation in limiting the spread of the melanie morphs are discussed and evidence is presented to show that predation by birds on ladybirds occurs more frequently than previously supposed.In conclusion it is proposed that the melanie frequency of a population is the result of the interaction of a number of factors whose importance varies from locality to locality.

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Polymorphism due to selection of varying direction

Cited by 436 publications

References 1 publication

The quantitative genetics of floral characters in Mimulus guttatus

The quantitative genetics of floral characters in Mimulus guttatus

The Genetic Architecture of Resistance to Desiccation in Populations of Drosophila melanogaster and D. simulans

Selection against the melanic morphs of Adalia bipunctata (two-spot ladybird): A review and some new data

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