Biology subjects

Tam, K. L.

Publications and source records attributed to Tam, K. L..

4 recordsLinked to original sources

bioRxiv2026

Development and assessment of tailored illustrations to enhance community understandings of genetics topics

ObjectivesEffective communication about genetics concepts is essential for collaborative anthropological genetics research. However, communication can be challenging because many ideas are abstract and may be especially unfamiliar to communities with limited access to formal education. Indeed, there are no widely adopted models for communicating such information, nor a clear understanding of the social factors that may shape participant engagement. Here, we conducted a qualitative and quantitative, community-driven study to understand how illustrations can be useful to support concept sharing with two Indigenous groups--the Orang Asli of Peninsular Malaysia and the Turkana of Kenya. MethodsWe used a two phase approach to create and evaluate how illustrations can bolster communication about genetics concepts. First, we created images illustrating answers to frequently asked questions about genetics, iteratively updating the illustrations based on participant feedback. Second, we conducted 92 interviews to evaluate the finalized illustrations effectiveness. Finally, we analyzed the interview data using thematic analyses, multivariable modeling, and multiple correspondence analyses to identify patterns in participant understanding and feedback, including age, sex, market integration, and schooling. ResultsParticipants reported high interest in genetics research (92%) and broadly positive perceptions of the illustrations. Familiar, locally-grounded imagery was preferred and associated with greater perceived clarity, while more technical illustrations were more frequently reported as confusing. Quantitative analyses showed strong internal consistency across measures of engagement and understanding, with modest variation by degree of market-integration, schooling, and sex. DiscussionOur findings demonstrate that community-specific visualizations, co-developed through iterative feedback, can effectively support engagement with genetics research in participant communities.

scientific communication and education↗

bioRxiv2026

Divergent Biological Consequences of APOE Isoforms Across Industrialized and Non-Industrial Environments

The apolipoprotein {varepsilon}4 (APOE {varepsilon}4) isoform directly alters cholesterol and immune biology and is associated with an increased risk of neurodegenerative and cardiometabolic disease in industrialized settings; nevertheless, APOE {varepsilon}4--which is ancestral in humans--has persisted over evolutionary time. One potential explanation is that the costs and benefits of APOE {varepsilon}4 were significantly different in the environments in which humans evolved compared to those we experience today. In support, previous work has suggested that living in a high pathogen environment, engaging in high levels of physical activity, or eating a low fat diet can dampen the detrimental effects of APOE {varepsilon}4, and has revealed positive effects for fertility. However, direct tests of whether APOE isoforms are associated with different biological outcomes in non-industrial versus industrialized contexts are lacking. Working with the Turkana of Kenya and the Orang Asli of Peninsular Malaysia--two Indigenous groups in which individuals of shared ancestry span a continuum of subsistence, non-industrial to urban, industrialized lifestyles--we investigated how APOE genotypes impact cholesterol, immunological, and reproductive traits and tested for genotype x environment (GxE) interactions. First, we confirmed established genotype effects across lifestyles, showing that more APOE {varepsilon}4 alleles are associated with higher total cholesterol, higher LDL cholesterol, and lower HDL cholesterol. Second, we tested for lifestyle interactions, finding lifestyle-dependent effects of genotype on innate immune biomarkers in the Orang Asli but not Turkana. Finally, we show that more APOE {varepsilon}4 alleles are correlated with an extended reproductive lifespan, however this effect is relatively weak, is not consistent across populations, and does not correspond with a higher reproductive output. Together, our study provides evidence that industrialized environments can modify the biology of APOE {varepsilon}4; however, we find that APOE {varepsilon}4 is not universally beneficial in non-industrial contexts, highlighting the role of local environmental variation in determining its specific costs and benefits.

evolutionary biology↗

bioRxiv2025

Recent lifestyle change impacts sleep and circadian rhythms among the Indigenous peoples of Peninsular Malaysia

Sleep disorders are rising globally, but their lifestyle causes remain unclear. We recorded sleep-wake patterns via actigraphy from 1036 Orang Asli adults across 12 communities in Peninsular Malaysia undergoing market integration, marked by changes in permanent infrastructure (electricity and housing), digital technologies (smartphones), and labor practices (i.e., wage labor). We evaluated associations with sleep timing (onset, offset and regularity), quality (nighttime awakenings and waking after sleep onset) and quantity (sleep duration), while accounting for age and sex. Delayed and destabilized sleep timing was observed in communities with powerline access, also resulting in shorter sleep duration; paradoxically, it also improved sleep quality, suggesting increased homeostatic pressure. Age and sex were strong and consistent predictors of sleep variation: older adults had earlier, shorter, and more consistent, consolidated sleep patterns. Men displayed later and shorter sleep patterns than women, likely reflecting gendered divisions of labor among the Orang Asli. Despite averaging relatively few hours slept (6 hrs), Orang Asli exhibited relatively efficient sleep, potentially challenging the notion that longer sleep is universally beneficial. These findings underscore the complex interplay of biology, ecology, and culture in shaping sleep and circadian rhythms. SignificanceA comprehensive cross-sectional study of sleep across a pronounced lifestyle gradient among Malaysias Indigenous Orang Asli populations reveals new insights into the drivers of human sleep and circadian rhythms. Lifestyle changes with market integration, particularly access to electricity, resulted in delayed bedtime and shortened sleep duration, yet enhanced sleep consolidation. Consistent with cross-cultural evidence, aging resulted in earlier bedtimes, earlier rising times, and less sleep. Our findings contribute to debates about the adaptability of human circadian rhythms and challenge universal models of optimal sleep duration.

physiology↗

bioRxiv2025

Early life environments shape adult cardiometabolic health during rapid lifestyle change

Early life environments can have long-lasting impacts on health and fitness, but the evolutionary significance of these effects remains debated. Two major classes of explanations have been proposed: developmental constraints (DC) explanations posit that early life adversity limits optimal development, leading to long-term costs, while predictive adaptive response (PAR) explanations posit that organisms use early life cues to predict adult conditions, resulting in detriments when adult environments do not match expectations. We tested these hypotheses using anthropological and biomedical data for the Orang Asli--the Indigenous peoples of Peninsular Malaysia--who are undergoing a rapid but heterogenous transition from non-industrial, subsistence-based livelihoods to more industrialized, market-integrated conditions. Using questionnaire data, we show that this shift creates natural variation in the degree of similarity between early life and adult environments. Using anthropometric and health data, we find that, more rural, subsistence-based early life environments are associated with shorter stature but better adult cardiometabolic health. Applying a quadratic regression framework, we find support for DC but not PAR in explaining adult cardiometabolic health, echoing findings and conclusions from other long-lived species. Overall, our results suggest that early life conditions can provide additive protection against common health issues associated with urban, industrialized lifestyle exposure.

evolutionary biology↗