Biologists unlock 51.7-million-year-old Genetic Secret

Charles Darwin proposed a hypothesis "that some species with two distinct forms of flower, where male and female reproductive organs were of differing lengths, and evolved that way to promote out-crossing by insect pollinators". Darwin coined the term 'heterostyly' because of his understanding of the two forms of flower known as pins and thrums and succeeding studies aided in building the foundation of modern genetics.

Researchers at the University of East Anglia studies the genetic code of these species' to discover what makes them that way, through an event that happened about 51 million years ago. Professor Philip Gilmartin from UEA reported that they have pinpointed the supergene responsible for this phenomenon, on the S locus. Supergenes are a group of closely related genes that can typically have related functions. Researchers worked to sequence the genome of the Primula attempting to recognize the supergene responsible for the different flower morphs.

Professor Gilmartin explained that his team found more than just the supergene, they found it is distinct to only one flower form, the thrum. He also stated that studying the genetics of flower development and reproduction can expand our knowledge of pollination which is the foundation of biodiversity and food security.

During the researchers pursuit for the genes in charge of heterostyly, they managed to date the original mutation to 51.7 million years ago. When they found the S locus, they discovered it was closely related to the gene responsible for being in command of the identity on pedals on a Primula flower. This gene was duplicated and inserted into the S locus and mutated to control the position of the anther in the flower.  The team was able to date how long ago the mutation occurred because they found the duplicated gene.

It's fascinating to read about the origins of different forms of flowers. I never thought that flowers had genes that expressed phenotypes the way humans do. Also, it's wonderful that this discovery could expand knowledge of food security which can improve the lives of humans. I hope to see study like this one carried out in the future on more species of flowers. One can never know what they will discover!