A0318
Title: Joint analysis of amplitude and phase variations in function-valued traits in quantitative genetics
Authors: Yilin Chen - Kings College London (United Kingdom) [presenting]
Davide Pigoli - King's College London (United Kingdom)
Abstract: Quantitative genetics is the study of continuous traits and the statistical analysis of the relative contributions of genetic and environmental effects to phenotypic variations. Function-valued traits, such as growth curves, are described as a function of a continuous index. Such traits, by nature, can be assessed for continuous genetic variation using a quantitative approach. However, growth curves from different individuals often present variability in both amplitude and phase. A conventional framework can be used, where curves are first registered and then the aligned data are analyzed. Nonetheless, this has the downside of ignoring phase variations in the genetics analysis. To include phase variations in analysis, the proposed method considers the aligned curve and the warping function (mapping the aligned curve to the original observation) as a joint functional object. A functional mixed-effects model that uses functional combined principal components as the data-driven basis is extended to genetically correlated data for this purpose. The proposed procedure is explored in simulations and applied to a real-case study of growth trajectories of red flour beetles.
