It is now abundantly clear that the microbes that live in our bodies are critical parts of our lives and our health. The study of these microbes and their genes—the so-called microbiome—has never been more popular. It’s also very WEIRD.

That’s not to say it is odd or unusual. WEIRD is an acronym, which stands for Western, Educated, Industrialized, Rich, and Democratic. It means that scientists have largely analysed the microbes of volunteers from the richest parts of the world. Only a few studies have looked beyond the West, at places like Burkina Faso, Venezuela, Bangladesh, and Malawi.

This matters because we’re getting a very distorted view of the human microbiome—one based on an unrepresentative slice of humanity at