Effects of Disruptive Selection: The Experimental Production of a Polymorphic Population

Thoday, J. M.

doi:10.1038/1811124a0

Cited by 34 publications

(9 citation statements)

References 5 publications

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“…Providing differences in natural selection are great enough they can maintain differences between populations between which there is considerable gene flow. This has recently been demonstrated experimentally in populations of Drosophila (Thoday, 1958). The other point to be considered is that recorded values for gene flow in wind pollinated plants are much less than might be expected.…”

Section: The Relative Importance Of the Various Factors Causing Diffementioning

confidence: 92%

POPULATION DIFFERENTIATION IN AGROSTIS TENUIS SIBTH

Bradshaw

1959

New Phytologist

114

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In order to investigate the pattern of population differentiation in Agrostis tenuis, sixty tillers were collected from each of thirty-three areas mainly in central Wales. These were grown under garden conditions in Aberystwyth. In a subsequent experiment five of these areas were sampled again by tillers, and at the same time sampled by seed. These samples were grown under garden conditions in Bangor.Numerous differences between these population samples were recorded. The main conclusions are as follows:(i) The environment is the dominating factor in determining population differentiation.(ii) Although the distribution is continuous, distances of about 50 m or less are sufficient to effectively isolate populations from one another.(iii) Thus the species is able to evolve under the influence of natural selection in response to very local variations in environment.(iv) Since the environment is a graded patchwork of different conditions, the pattern of differentiation is similar.(v) It is, therefore, not possible to classify effectively such intraspecific variation.(vi) It is likely that this situation is to be found in most other outbreeding continuously distributed plant species occupying a wide range of habitats.

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Section: The Relative Importance Of the Various Factors Causing Diffementioning

confidence: 92%

POPULATION DIFFERENTIATION IN AGROSTIS TENUIS SIBTH

Bradshaw

1959

New Phytologist

114

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“…INTRODUCTION IT has already been shown experimentally (Thoday, 1958, that disruptive selection (Mather, 1953) or centrifugal selection (Simpson, 1944) can increase and that stabilising (or centripetal) selection can reduce the genetic flexibility of a population. The effects of disruptive selection can also extend so far as to render a population polymorphic (Thoday and Boam, 1959), as Mather (i) had expected on general grounds.…”

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confidence: 99%

Effects of disruptive selection

Thoday

1960

Heredity

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“…In so far as different interdependent classes of phenotype are selected, it is to be expected that disruptive selection, given appropriate genetic variation, will produce a polymorphic population. It has been shown experimentally (Thoday, 1958a(Thoday, , 1959(Thoday, , 1960; Thoday and Boam, that this is so. On the other hand, if different independent phenotypes are selected, disruptive selection might result in the development of physiological isolation between them.…”

Section: Introductionmentioning

confidence: 90%