Monkeyflowers glow in a rich assortment of colors, from yellow to pink to deep red-orange. But about 5 million years ago, some of them lost their yellow. In the Feb. 10 issue of Science, UConn botanists explain what happened genetically to jettison the yellow pigment, and the implications for the evolution of species.

Monkeyflowers are famous for growing in harsh, mineral-rich soils where other plants can’t. They are also famously diverse in shape and color. Monkeyflowers also provide a textbook example of how a single-gene change can make a new species. In this case, a monkeyflower species lost the yellow pigments in the petals but gained pink about 5 million years ago, attracting bees for pollination. Later, a descendent species accumulated mutations in a gene called YUP that recovered the yellow pigments and led to production of red flowers. The species stopped attracting bees. Instead, hummingbirds pollinated it, isolating the red flowers genetically and creating a new species.

UConn botanist Yaowu Yuan and postdoctoral researcher Mei Liang (currently a professor at South China Agricultural University), with collaborators from four other institutes, have now shown exactly which gene changed to prevent monkeyflowers from making yellow. Their research, published this week in Science, adds weight to a theory that new genes create phenotypic diversity and even new species.