Being stressed or afraid may alter a person’s usual scent. That can throw dogs off the person’s track. People with a particular version of a gene may have a bigger change in odor when stressed, data show.

We inherit genes from our parents. Genes are like a recipe that’s passed along from one generation to the next. But the number of genes doesn’t explain why we are more complex than simple animals or bacteria.

Scientists engineered a plant called thale cress (above) to be nearly always on alert to leaf-eating predators. In the lab, these plants grew smaller and made fewer viable seeds than normal.

The malaria-carrying mosquito Anopheles gambiae’s days may be numbered. Scientists have devised a gene drive that wiped out the mosquito’s populations in lab tests.