Methods for the Comparative Analysis of Variation Patterns

Cheverud, James M.; Wagner, Günter P.; Dow, Malcolm M.

doi:10.2307/2992282

Cited by 272 publications

(305 citation statements)

References 38 publications

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“…We then calculated trait integration as the variance of the eigenvalues of the trait correlation matrices [INT ¼ V (l)] [32] in each trait module for all floral forms. To control for differences in sample size between the floral forms investigated and between trait modules, we subtracted the expected eigenvalue variance under the hypothesis of random covariation of traits [Exp(INT) ¼ (number traits 2 1)/N] from INT for each form to obtain the corrected INT values [32,33]. These were expressed as % of maximum INT.…”

Section: (D) Assessing Trait Divergence Between Floral Formsmentioning

confidence: 99%

Floral trait variation and integration as a function of sexual deception inGorteria diffusa

Ellis

Jager

Mellers

et al. 2014

Phil. Trans. R. Soc. B

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Phenotypic integration, the coordinated covariance of suites of morphological traits, is critical for proper functioning of organisms. Angiosperm flowers are complex structures comprising suites of traits that function together to achieve effective pollen transfer. Floral integration could reflect shared genetic and developmental control of these traits, or could arise through pollinator-imposed stabilizing correlational selection on traits. We sought to expose mechanisms underlying floral trait integration in the sexually deceptive daisy, Gorteria diffusa , by testing the hypothesis that stabilizing selection imposed by male pollinators on floral traits involved in mimicry has resulted in tighter integration. To do this, we quantified patterns of floral trait variance and covariance in morphologically divergent G. diffusa floral forms representing a continuum in the levels of sexual deception. We show that integration of traits functioning in visual attraction of male pollinators increases with pollinator deception, and is stronger than integration of non-mimicry trait modules. Consistent patterns of within-population trait variance and covariance across floral forms suggest that integration has not been built by stabilizing correlational selection on genetically independent traits. Instead pollinator specialization has selected for tightened integration within modules of linked traits. Despite potentially strong constraint on morphological evolution imposed by developmental genetic linkages between traits, we demonstrate substantial divergence in traits across G. diffusa floral forms and show that divergence has often occurred without altering within-population patterns of trait correlations.

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Section: (D) Assessing Trait Divergence Between Floral Formsmentioning

confidence: 99%

Floral trait variation and integration as a function of sexual deception inGorteria diffusa

Ellis

Jager

Mellers

et al. 2014

Phil. Trans. R. Soc. B

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show abstract

“…A Pearson product-moment correlation between corresponding off-diagonal nonredundant elements of two correlation matrices was employed to measure the pattern similarity of corresponding genetic and phenotypic correlation matrices (cf. Lofsvold, 1986;Cheverud, 1988Cheverud, , 1989Kohn & Atchley, 1988;Cheverud et al, 1989;Cowley & Atchley, 1990;Wagner, 1990;Roff, 1995). The matrix correlation which measures the similarity of the arrangement of elements of different magnitudes in two matrices is given by…”

Section: Data Analysesmentioning

confidence: 99%

Genetic and phenotypic correlations in plants: a botanical test of Cheverud's conjecture

Waitt

Levin

1998

Heredity

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A survey of the agricultural and evolutionary literature was undertaken to determine the extent to which phenotypic correlations reflect their genetic counterparts in plants. More than 4000 phenotypic and genetic correlations representing 27 different plant species and over 40 years of research were analysed. In 74 per cent of the comparisons, the arrangement of elements of different magnitudes in genetic and phenotypic correlation matrices was more similar than would be expected by chance alone. In addition, the overall magnitude of correlation was greater in genetic correlation matrices than in phenotypic correlation matrices in 85 per cent of the comparisons. Several studies which reported correlations within and among distinct suites of traits provided the opportunity to evaluate correlations among functionally or developmentally related characters. It was determined from these studies that traits belonging to the same suite of characters were more highly genetically and phenotypically correlated than traits from different suites.

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“…Em relação às matrizes de correlação, a similaridade foi acessada através do método da correlação de matrizes elemento a elemento (CM; Cheverud et al, 1989). A correlação entre as matrizes par a par foi obtida através da equação abaixo (Sneath e Sokal, 1972;Cheverud et al, 1989):…”

Section: Similaridade Entre Matrizesunclassified

“…A correlação entre as matrizes par a par foi obtida através da equação abaixo (Sneath e Sokal, 1972;Cheverud et al, 1989):…”

Section: Similaridade Entre Matrizesunclassified

“…A significância estatística foi verificada através do teste de Mantel, que consistiu em: 1) correlacionar uma das matrizes originais com 10000 matrizes geradas através da permutação de linhas e colunas da outra matriz original; 2) a correlação entre as duas matrizes originais foi comparada com a distribuição empírica de correlações gerada a partir do procedimento descrito acima. Se tal correlação excedeu 95% (ou 99%) da distribuição ela foi considerada significativa (Cheverud, 1988;Cheverud et al, 1989).…”

Section: Similaridade Entre Matrizesunclassified

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Análise morfológica craniana de Xenartha atuais e extintos: inferências evolutivas e funcionais

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Methods for the Comparative Analysis of Variation Patterns

Cited by 272 publications

References 38 publications

Floral trait variation and integration as a function of sexual deception inGorteria diffusa

Floral trait variation and integration as a function of sexual deception inGorteria diffusa

Genetic and phenotypic correlations in plants: a botanical test of Cheverud's conjecture

Análise morfológica craniana de Xenartha atuais e extintos: inferências evolutivas e funcionais

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