Andrew William Best

Grant Type

Dissertation Fieldwork Grant

Institutional Affiliation

Massachusetts, Amherst, U. of

Grant number

Gr. 9891

Approve Date

October 24, 2019

Project Title

Best, Andrew (Massachusetts, Amherst, U. of) "Diversity and Evolution of Human Eccrine Sweat Gland Density"

Increased eccrine sweat gland density was a key adaptation in the evolution of genus Homo, helping early humans to manage increasing thermal loads associated with bigger brains and expanded locomotor activity in hot conditions. As humans dispersed out of Africa and into novel habitats sweat gland biology likely changed to suit local environmental conditions. In addition, previous researchers proposed that phenotypic plasticity may play an important role in shaping sweat gland diversity- specifically, living in hot early childhood climates could elicit greater gland activation, resulting in relatively high active sweat gland density. Surprisingly, we know little about the evolution and diversity of this unique human trait. My project aims to measure eccrine sweat gland diversity in modern humans and assess the relative influence of evolutionary processes and phenotypic plasticity. I am recruiting volunteers from various geographic ancestries and childhood climate backgrounds and measuring sweat gland density via pharmacological stimulation. To quantify the relationship between sweat gland density and ability to dissipate heat, I am recruiting heat-trained endurance runners for exercise testing in a metabolic chamber, measuring heat production and dissipation. Thus, my project promises to elucidate the drivers of diversity in this important human trait and its physiological significance.