Double reduction at the mid locus in Lythrum salicaria

Fyfe, Viviane C

doi:10.1038/hdy.1953.34

Cited by 10 publications

(7 citation statements)

References 10 publications

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“…Style length is governed by the S and M loci, with the long-styled morph (hereafter the L morph) ssmm, the mid-styled (M) morph ssM-, and the short-styled (S) morph S---. Lythrum salicaria has tetrasomic inheritance at both style morph loci with no linkage, and double reduction was estimated at 10 per cent and 2.5 per cent for the S and M loci, respectively (Fisher & Mather, 1943;Fisher, 1949;Fyfe, 1953). Models incorporating tetrasomic inheritance (with double reduction) gave results identical to those incorporating diploid inheritance (see also Eckert & Barrett, 1992;Eckert et al, 1996).…”

Section: Computer Mode/ssupporting

confidence: 60%

Frequency-dependent selection on morph ratios in tristylous Lythrum salicaria (Lythraceae)

1996

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In the plant sexual polymorphism tristyly, disassortative mating among floral morphs should result in frequency-dependent selection leading to equal frequencies of the three morphs in populations at equilibrium. Direct evidence for frequency-dependent selection in natural populations is, however, lacking. Here we attempt to detect frequency-dependent selection in rapidly expanding populations of the invasive wetland herb Lythrum salicaria. Deterministic computer models were used to assess the expected change in morph ratios. Model results were tested with data from 24 Ontario populations each with an initially low frequency (<0.11) of one morph sampled over a 5-year interval. On average, morph evenness and the frequency of the rare morph increased significantly between samples (mean frequency change = + 0.034; range = -0.045 to + 0.278). As predicted by the theoretical model, changes in both morph evenness and the frequency of the rare morph were positively correlated with initial morph frequencies. However, no evidence was obtained for expected correlations with the magnitude of the 5-year increase in population size. The results provide the first empirical demonstration of frequency-dependent selection on morph ratios in natural populations of a heterostylous plant.

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Section: Computer Mode/ssupporting

confidence: 60%

Frequency-dependent selection on morph ratios in tristylous Lythrum salicaria (Lythraceae)

1996

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“…The genetic control is carried by two loci, M and S (with linkage in Oxalis valviviensis and independence in Lythrum salicaria, as shown by Fisher and Martin 1948), each with a dominant and a recessive allele. In L. salicaria, where the loci are unlinked, inheritance is tetrasomic, with 10% double reduction at both loci (Fyfe 1953). Long-styled plants have the recessive alleles of both genes, while individuals with mid-styles lack the dominant S allele but are either heterozygous or homozygous dominant at the M locus.…”

Section: Tristylymentioning

confidence: 99%

Incompatibility and Incongruity in Wild and Cultivated Plants

Nettancourt

2001

654

524

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“…Lythrum salicaria exhibits tetrasomic inheritance at both style morph loci, with no linkage or dosage effects (Fisher and Mather, 1943;Fisher and Martin, 1947). Double reduction has been estimated at 10% for the S locus (Fyfe, 1953) and 2.5% for the M locus (Fisher, 1949). One version of our computer model simulated tetrasomic inheritance with 5% double reduction at both loci, and no linkage between them.…”

Section: Computer Modelsmentioning

confidence: 99%

STOCHASTIC LOSS OF STYLE MORPHS FROM POPULATIONS OF TRISTYLOUSLYTHRUM SALICARIAANDDECODON VERTICILLATUS(LYTHRACEAE)

Eckert¹,

Barrett²

1992

Evolution

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Despite the theoretical importance of stochastic processes in evolution there have been few empirical studies of the interaction between genetic drift and selection on the maintenance of polymorphisms in plant populations. We used computer models to investigate the interaction between drift and frequency-dependent selection in affecting style morph frequencies in populations of tristylous species. Drift produces a distinct pattern of morph frequency variation involving: 1) the loss of the S morph and, to a lesser extent, the M morph; 2) no consistent bias in frequencies within populations; 3) a restricted pattern of variation involving a deficiency of one morph and equal excesses of the other two. Morph frequencies were surveyed in 137 populations of Lythrum salicaria from both its native range in Europe (N = 35) and recent adventive range in Ontario (N = 102), and 133 populations of Decodon verticillatus from four regions in eastern North America with different glacial histories to assess these theoretical predictions. There was a negative relationship between morph loss and population size in both species; the relationship was weaker in D. verticillatus than in L. salicaria. Morph loss was more frequent in the adventive than native range of L. salicaria, and in populations of D. verticillatus from glaciated northern regions compared with the unglaciated southern portion of its range. Simulations incorporating variation in life history, regeneration strategy and mating patterns revealed that the degree of morph loss was strongly influenced by year to year survival, clonal propagation, self-fertilization and departures from disassortative mating. Comparing the pattern of morph frequency variation between species supported these predictions. Morph loss was lower in self-incompatible L. salicaria (0% in Europe; 23% in Ontario), which reproduces through seed compared to self-compatible, clonal D. verticillatus (52%). A stochastic model provides the most parsimonious explanation for observed patterns of morph frequency variation in both species.

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Double reduction at the mid locus in Lythrum salicaria

Cited by 10 publications

References 10 publications

Frequency-dependent selection on morph ratios in tristylous Lythrum salicaria (Lythraceae)

Frequency-dependent selection on morph ratios in tristylous Lythrum salicaria (Lythraceae)

Incompatibility and Incongruity in Wild and Cultivated Plants

STOCHASTIC LOSS OF STYLE MORPHS FROM POPULATIONS OF TRISTYLOUSLYTHRUM SALICARIAANDDECODON VERTICILLATUS(LYTHRACEAE)

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