Health and Medicine
PUBLISHED
Where you live may have big impacts on how fast you age. A global team of scientists led by Stanford University have discovered that ethnicity and geography impact the human body, from our metabolism and immunity to our gut microbiota and even our biological aging. The results reveal the complex relationship between genetics and the environment and may offer clinicians a better way to understand health care for different populations.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.Humans are phenotypically diverse, meaning that they show a wide range of observable characteristics. Advances in molecular research have allowed scientists to create comprehensive datasets using an approach called “multiomics”, which measures everything from genes and proteins to gut bacteria and metabolic activity, to show how humans differ from one another on a molecular level.
However, most existing studies have tended to focus on people from similar backgrounds or on patients with particular diseases. This means scientists have a limited understanding of how genetic ancestry and geographic environments can jointly impact biology and health in otherwise healthy people.
In this new study, scientists used the multiomics method to examine 322 healthy people from Europe, East Asia, and South Asia, which allowed them to build the most detailed picture yet of how genetic ancestry and environment shapes our biology. By focusing on people of the same genetic ancestry living in different continents, the team were able to separate the effects of DNA from the influence of the environment with new, unparalleled clarity.
"For the first time, we have deeply profiled people from around the world," co-senior author Michael Snyder, Professor in Genetics at Stanford University, explained in a statement. "This enables us to see what properties such as metabolites and microbes are correlated with ethnicity and which ones with geography."
The results identified some ethnicity-associated molecular signatures. For instance, South Asian participants showed higher levels of pathogen exposure, while those with European ancestry demonstrated richer gut microbial diversity and higher levels of metabolites associated with cardiovascular disease. These patters were consistent regardless of where participants lived, suggesting a strong genetic root that shapes human molecular identity.
Where people live also leaves a significant imprint on their biology. Geographic relocation – referring to people who no longer live on the continent where their ancestors lived – was associated with important shifts in metabolic and lipid networks, and an altered gut microbiome.
But the most dramatic discovery related to geography and biological aging. East Asians living outside Asia were found to be biologically older than those who stayed in Asia. Europeans showed the opposite outcome, appearing biologically younger when they lived outside Europe.
The results suggest environment and genetic ancestry interact in unexpected ways that could speed up or slow down aging.
The team also discovered a never-before-seen relationship between a telomerase gene involved in cellular aging and a specific gut microbe, connected through a lipid molecule known as sphingomyelin. This unexpected three-way connection could mean there is a molecular chain reaction allowing gut bacteria to influence how quickly cells age.
The results offer new resources for precision medicine, revealing just how important it is for healthcare to be tailored to genetic ancestry and environment. This adds more pressure to move away from one-size-fits-all models.
The datasets for this study are freely available to other researchers and clinicians. The hope is that it will allow for the creation of more accurate diagnostics, treatments, and prevention strategies that are tailored to the individual.
"What this study shows, more clearly than ever before, is that our biology is shaped by a combination of both our genetic ancestry and the places we live," study coauthor Professor Richard Unwin, from the University of Manchester, explained in a statement sent to IFLScience.
"We were struck by how consistently ethnicity influenced immunity, metabolism and the microbiome, even when people moved thousands of miles away," Unwin added. "However, it is equally clear that where we live can have substantial impacts on nudging key molecular pathways – even how our cells appear to age – in different directions depending on who you are. It proves that precision medicine must reflect real global diversity, not a single population."
The study is published in Cell.
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