Scientists have unlocked a 51.7-million-year old genetic secret to a landmark theory proposed by English naturalist Charles Darwin more than 150 years ago. Researchers have identified the cluster of genes responsible for reproductive traits in the Primula flower. Darwin hypothesised that some plant species with two distinct forms of flower, where male and female reproductive organs were of differing lengths, had evolved that way to promote out-crossing by insect pollinators. […]