About a decade ago, de Mendoza even searched for these genes in protists and similar unicellular organisms during his PhD research. He only had three sequenced genomes to search at the time ...

All have a set of very similar genes (the homeobox genes) that define their basic body plan. As they grow, the differences that will distinguish the embryos as adults become more and more apparent.

The more similar the men’s and women’s immune system genes were, the worse the T-shirt stank to the women. There is a sound evolutionary explanation for this: If parental immune genes are too ...