A dog tumor that became a free-living parasite picked up myriad mutations, but has since stabilized.

Ant, bee, and wasp queens emit a similar class of pheromones that sterilize their workers, hinting at a shared ancestry for these chemicals.

A new analysis suggests that placental mammals originated while dinosaurs were dominant, contradicting a recent high-profile study.

Fossilized skin reveals the colors of three extinct marine reptiles

The genome of Amborella trichopoda—the sister species of all flowering plants—provides clues about this group’s rise to power.

Dust-borne bacteria from houses with dogs can prevent allergies in mice by changing their gut microbes.

A 400,000-year-old mitochondrial genome adds new twists to scientists’ picture of early human evolution.

Mouse mothers can improve their pups’ memories by altering levels of immune chemicals in their milk.

HIV-1 evades the immune system with a protein shield, which can be lifted.

New analysis suggests that domestic dogs evolved from European wolves that interacted with human hunter-gatherers.

Cells that temporarily restrain their immune systems give babies’ gut bacteria a chance to settle down. 

Common mutations in metastasized breast tumors suggest how the cancer can develop resistance to frontline drugs.