Fourth Mendel pea gene characterised
An international group of researchers based at the UK’s John Innes Centre (JIC – Norwich) has identified the mutant allele in a gene that controls flower colour in peas. It was used by Gregor Mendel in his initial studies of inheritance. In peas, two genes dubbed A and A2, act as transcription factors, regulating the production of anthocyanins. The accumulation of anthocyanin pigment molecules confers a purple colour to wild-type pea flowers. A rare mutation of just one nucleotide in a single gene, A, inhibits anthocyanin production, resulting in peas with white flowers. Mendel determined the segregation of heritable characteristics by tracking the appearance of different phenotypes, including white flowers, in descendants of hybrid peas.