Lui, K. F. H. | Search bioRxiv

bioRxiv2021

Quantitative multidimensional phenotypes improve genetic analysis of laterality traits

Handedness is the most commonly investigated lateralised phenotype and is usually measured as a binary left/right category. Its links with psychiatric and neurodevelopmental disorders prompted studies aimed at understanding the underlying genetics, while other measures and side preferences have been less studied. We investigated the heritability of hand, as well as foot, and eye preference by assessing parental effects (n [≤] 5 028 family trios) and SNP-based heritability (SNP-h2, n [≤] 5 931 children) in the Avon Longitudinal Study of Parents and Children (ALSPAC). An independent twin cohort from Hong Kong (n = 358) was used to replicate results from structural equation modelling (SEM). Parental left-side preference increased the chance of an individual to be left-sided for the same trait, with stronger maternal than paternal effects for footedness. By regressing out the effects of sex, age, and ancestry, we transformed laterality categories into quantitative measures. The SNP-h2 for quantitative handedness and footedness was .21 and .23, respectively, which is higher than the SNP-h2 reported in larger genetic studies using binary handedness measures. The heritability of the quantitative measure of handedness increased (.45) compared to a binary measure for writing hand (.27) in the Hong Kong twins. Genomic and behavioural SEM identified a shared genetic factor contributing to handedness, footedness, and eyedness, but no independent effects on individual phenotypes. Our analysis demonstrates how quantitative multidimensional laterality phenotypes are better suited to capture the underlying genetics than binary traits.

genetics↗

bioRxiv2018

Acquiring absolute pitch in adulthood is difficult but possible

Absolute pitch (AP) refers to the rare ability to name the pitch of a tone without external reference. It is widely believed that AP is only for the selected few with rare genetic makeup and early musical training during the critical period. Accordingly, acquiring AP in adulthood is impossible. Previous studies have not offered a strong test of the effect of training because of issues like small sample size and insufficient training. In three experiments, adults learned to name pitches in a computerized and personalized protocol for 12 to 40 hours. They improved considerably, with a continuous distribution of learning progress among them. 14% of the participants (6 out of 43) were able to name twelve pitches at accuracy of 90% or above, comparable to that of AP possessors as defined in the literature. In general, AP learning showed classic characteristics of perceptual learning, including generalization of learning dependent on the training stimuli, and sustained improvement for at least one to three months. Overall, the finding that AP continues to be learnable in adulthood calls for reconsidering the role of learning in the occurrence of AP. The finding also pushes the field to pinpoint and explain, if any, the differences between the aspects of AP more trainable in adulthood and the aspects of AP that are potentially exclusive for the few exceptional AP possessors.

animal behavior and cognition↗