Roses are red, violets are blue, but why aren't snapdragons orange? Norwich scientists from the John Innes Centre (JIC) and the University of East Anglia (UEA) in collaboration with the Université Paul Sabatier (Toulouse, France) have developed a pioneering computer modelling technique that traces the evolutionary paths underlying flower colour variation in the model plant snapdragon (Antirrhinum).
Their research, funded by the BBSRC and published today in the journal
Science, shows how flower colour diversity has evolved in natural populations of these plants in the Pyrenees.
In the wild, only the plants with the most attractive flower colours are able to reproduce and thrive because the insects that pollinate them prefer certain colours. The bees that pollinate snapdragon find magenta and yellow flowers the most attractive; they do not find colours such as orange attractive and so flowers of this colour would not flourish in the wild due to lack of pollination. Scientists already know that natural colour variation is controlled by three genes: ROSEA and ELUTA affect the intensity and pattern of the magenta pigment anthocyanin and thirdly SULFUREA affects the distribution of the yellow aurone pigment. The researchers in this study wanted to understand how plants producing magenta or yellow flowers could evolve from a common ancestor without producing in-between non-attractive flower colours such as orange.
"This is a totally different way of looking at evolution and could lead to a better understanding of the rules that govern biodiversity" explains Coen, "If we can comprehend how Antirrhinum genes interact in their natural habitat, it may help us in the future to better preserve genetic diversity".
The team led by Enrico Coen (JIC) and Andrew Bangham (UEA) combined molecular, genetic and computational approaches to analyse flower colour variation in natural populations of snapdragon. Using a traditional model, a plot of evolutionary fitness for this study appears to have two peaks: one at the magenta end of the colour spectrum and a second peak at the yellow end, with a trough in the middle representing non-attractive intermediate colours such as orange. As a result, for a plant to evolve from producing magenta flowers to yellow ones it would first have to pass through the trough and produce non-attractive orange flowers before developing yellow ones. However, as Bangham points out, “There are computational methods for understanding and visualising high-dimensional problems that provide new insights”. With these, a more realistic model was created and the researchers discovered that different attributes (phenotypes) that previously appeared as separate peaks in the adaptive landscape, were in fact connected by paths in higher dimensions, forming a U-shaped cloud, with one arm representing magenta connected to the second arm representing yellow. Using this new model, the scientists could trace the evolutionary path that linked these two apparently distinct colour attributes.
"We now understand how these plants can evolve to produce different colours whilst staying attractive to pollinating insects – we've found that colour is variable but constrained to a defined path" states Enrico Coen. But if pollinators prefer certain coloured flowers, why aren't all flowers the same colour? "We still do not know precisely why flower colours should vary in the first place," says Coen, "it could be due to drifting of colours from one to another by accumulation of genetic errors, or alternatively there could be a selective advantage for certain colours in different environments".
The researchers are now applying this new way of modelling evolution to other phenotypes, allowing them to identify how apparently distinct attributes are linked through evolution.
Source: John Innes Centre
Related stories:
Fast learning bumblebees reap greater nectar rewards
The speed with which bees learn affects their ability to collect food from flowers, according to a new study from Queen Mary, University of London.
New research into plant colors sheds light on antioxidants
Scientists have made an important advance in understanding the genetic processes that give flowers, leaves and plants their bright colours. The knowledge could lead to a range of benefits, including better understanding of the cancer-fighting properties of plant pigments and new, natural food colourings. The research is highlighted in the new issue of Business from the Biotechnology and Biological Sciences Research Council (BBSRC).
Bees hit a purple patch
A bee’s favourite colour can help them to find more food from the flowers in their environment, according to new research from Queen Mary, University of London.
Found - the apple gene for red
CSIRO researchers have located the gene that controls the colour of apples – a discovery that may lead to bright new apple varieties.
Bees like it hot
Research from Queen Mary, University of London has shown that bees prefer to visit warm flowers, and can learn to use colour to predict floral temperature before landing.
Plant gene replacement results in the world's only blue rose
Australian and Japanese researchers have demonstrated the application of RNAi technology for gene replacement in plants, developing the world's only blue rose.
Flexi display technology is now
Rigid television screens, bulky laptops and still image posters are to be a thing of the past as new research, published today, Thursday, 2 October, in the
New Journal of Physics, heralds the beginning of a technological revolution for screen displays.
Autumn colours may be a safety mechanism for trees, say researchers
(PhysOrg.com) -- One sign of autumn is the leaves turning colour, but why do some turn red? This question has baffled biologists for decades, and many ideas have been put forward to explain leaf colour change in autumn. Now, Dr Thomas Döring, a visiting post-doc in the Division of Biology at Imperial College London, has come up with a new possible explanation.
