Finding the key to Mendel’s pea flowers
14 Jun, 2011
Source: Plant & Food Research
Plant & Food Research scientists have helped discover the key to one of biology’s most well known experiments – the gene that controls pea flower colour – followed by Mendel in his studies of inheritance.
150 years ago, Gregor Mendel planted peas segregating for flower colour. An international group of scientists has revealed the underlying molecular genetics behind this experiment, identifying genes that control flower colour in pea plants.
“Mendel is known as the father of modern genetics, using pea characteristics to demonstrate inheritance patterns,” says Dr Roger Hellens, Science Leader of the Genomics Group at Plant & Food Research.
Identifying pea genes that control flower colour
The purple colour of wild pea flowers and flowers of many other plants is a consequence of the accumulation of pigment molecules called anthocyanins, and the biochemistry of their production has been studied for many years. A research collaboration between scientists at Plant & Food Research, the John Innes Centre (JIC) in the UK, URGV in France and the USDA’s Agricultural Research Services revealed 2 pea genes, known as A and A2, that regulate the production of anthocyanins.
Comparing pea genes with other plants
A protein called a transcription factor that switches other genes on was shown to control flower colour. “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. This transcription factor, when mutated, becomes inactive, and anthocyanin is not produced, resulting in white flowers,” says Dr Hellens.
Previous work to identify similarities and differences between pea DNA helped gene discovery. “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. Finding a rare second allele was important for independent confirmation of the identity of the gene,” says Professor Noel Ellis, associate head of Crop Genetics at JIC. “This is the 4th of Mendel’s 7 genes to be characterised at the molecular level: it is also the second where JIC has been involved.”
- 14 June 2011