For about 70 years, breeders have selected tomato varieties with uniformly light green fruit before ripening. These tomatoes then turn red evenly as they ripen, and they look nice in a supermarket display.

Researchers now have pinpointed the molecular changes responsible for this “uniform ripening” trait of many modern tomatoes. But these changes, they show, also reduce the fruit’s sugar content.

Researchers have pinpointed a genetic mutation that may help explain why some men are less fertile than normal, a new study in the 20 July issue of the journal Science Translational Medicine reports.

The gene encodes a protein called beta-defensin 126, which coats the surface of sperm and helps them penetrate cervical mucus in women. Men with a variant of this gene, called DEFB126, lack beta-defensin 126, making it much more difficult for sperm to swim through the mucus and join with an egg.