12/ TLDR: we identify widespread signatures of positive selection associated with 13 different micronutrients at different timepoints in human evolutionary history, suggesting that micronutrients have been a powerful selective force in modern humans 🧬🌎🍎

11/ Side bar: this work was done as part of my PhD, under two incredible supervisors (@aidaandres.bsky.social
& Sergi Castellano) and I hope some of the joy of my time at @uclchildhealth.bsky.social & @ugiatucl.bsky.social translated into the paper

10/ If true, this has the potential to drive or exacerbate micronutrient-linked health disparities across populations - especially when over-farming and climate change continues to decrease soil quality. It is hard to ignore potential public/global health connotations🌎

9/ Why is this important? We suggest dietary micronutrients have shaped the recent evolution of humans and likely contributed to population differentiation in diet-related genes - possibly resulting in average differences in their micronutrient uptake, metabolism or regulation.

8/ In some cases, signatures of positive selection are identified in areas of the world with soil of known deficiencies or toxicities of micronutrients - potentially reflecting genetic adaptation to soil-driven micronutrient levels in the diet. Read our paper to see where 🤓

7/ Rather than isolated cases, we see evidence for monogenic and/or oligogenic adaptation for all micronutrients , across diverse geographic and temporal scales ⚠️

6/ We used methods informed by extensive simulations to identify signatures of positive selection in ~300 genes associated with 13 essential trace minerals in 40 diverse human populations, considering monogenic, oligogenic and polygenic selection 🧬

5/ We wanted to ask: have all micronutrients acted as selective pressures? Or only a few? And in which populations and timepoints? Is this likely to be driven by differing micronutrient levels in local soils? 🌎

4/ But soils can be extremely variable in their micronutrient content (even amongst really close-by environments!) - and have previously been suggested to drive some isolated examples of local adaptation to dietary micronutrients in human populations 🧬

3/ For much of human evolution, the amount of micronutrients in our diet have depended on the underlying soil content, since micronutrients are taken up by local plants and animals that then make up the human diet 🐔🍎🌽

2/ Micronutrients - including trace minerals and vitamins - are essential components in the human diet, needed in very small and precise quantities. Deficiencies can be super harmful, leading to stunted growth and increased risk of infectious, metabolic or respiratory diseases 🤒

1/ So pleased to share our paper on genetic adaptation to micronutrients in humans! Our biggest conclusion? Trace minerals in the diet have shaped human evolution far more than previously appreciated 🧬🌍👇
www.cell.com/ajhg/fulltex...

Jasmin Rees PhD chapter as a paper just out at the AJHG @ajhgnews.bsky.social, with Sergi Castellano, who first envisioned the study. Jas investigated signatures of human local genetic adaptation in hundreds of micronutrient-associated genes.