Yellow Evolution: Unique Genes Led to New Species of Monkeyflower

Published:08 Mar.2023 Source:University of Connecticut

Monkeyflowers are famous for growing in harsh, mineral-rich soils where other plants can't. They are also famously diverse in shape and color. And monkeyflowers 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 it is that changed to prevent monkeyflowers from making yellow. Their research, published this week, adds weight to a theory that new genes create phenotypic diversity and even new species. The YUP gene in question is found at a locus, or region, of the monkeyflower genome that has three new genes. These new genes are not found in species outside of this group. They are duplicates of other genes from other parts of the monkeyflower genome. In particular, YUP is a partial duplicate of a pre-existing gene that has nothing to do with color.