Mendel’s flower gene finally found

Gregor Mendel planted peas segregated for flower colour 150 years ago but he couldn’t pinpoint the gene that controls colour – now scientists think they’ve found it.

Left -wild-type pea flower. Right - white mutant pea flower

An international group of scientists have revealed the underlying molecular genetics behind Mendel’s famous experiment and have identified the genes that control flower colour in pea plants.

They discovered two genes – A and A2 – that regulate the production of pigment molecules called anthocyanins. The accumulation of anthocyanins gives wild type pea flowers – and many other types of flower – their purple colour.

“Mendel is known as the father of modern genetics, using pea characteristics to demonstrate inheritance patterns,” said Dr Roger Hellens from Plant & Food Research in New Zealand, “By comparing the pea DNA sequences to those of other well-characterised plants, such as petunia, we have determined that Mendel’s gene is a transcription factor that controls the anthocyanin biosynthesis pathway.”

When the transcription factor is muted and becomes inactive, anthocyanins are not produced and the flowers are white. The study used a collection of around 3,500 pea lines – some wild, cultivated and semi-cultivated – from the John Innes Centre(JIC), some dating back to the nineteenth century. This germplasm collection is a valuable genetic resource for scientists and plant breeders looking for improved pea varieties.

“We used information from our previous genotyping of the JIC pea germplasm collection to identify exotic lines where we would most likely find rare alleles of Mendel’s gene,” said Professor Noel Ellis from JIC, “Finding a rare second allele was important for independent confirmation of the identity of the gene.”

The JIC is now looking into the germplasm collection for genes and traits that could be used to make peas higher-yielding or of better quality.