16th August 2017- By Kenneth Macdonald
Scientists have discovered a brand new flower in Shetland.
It is a beauty.
A delicate golden bell of a flower, its throat flecked with tiny, blood-red spots – colours echoing the Lion Rampant.
It is a discreet beauty, though. Each flower is only slightly larger than a 50p piece.
Discreet and unique, because this is a new flower of Scotland. Or, more precisely, Shetland.
The flower was discovered by a team from Stirling’s department of biological and environmental sciences led by post-doctoral researcher Dr Violeta Simon-Porcar, working with associate professor Dr Mario Vallejo-Marin at Stirling and Dr James Higgins at Leicester University.
It is being referred to as “Shetland’s monkeyflower”, because it is larger and its flowers are more open than previous monkeyflowers.
Its ancestor was a non-native species introduced to the British Isles just a couple of centuries ago, probably from Alaska.
It was the period in which – not content with possessing large chunks of the globe – Britain tried to bring home much of its flora and fauna.
The results were mixed but the yellow monkeyflower – mimulus guttatus – literally took root and spread rapidly.
Then on Shetland something unusual happened. Mimulus guttatus doubled the number of its chromosomes.
It is a process known as genome duplication or polyploidy.
There lies the reason why the Shetland Monkeyflower has a bigger flower with a wider throat than its ancestors.
A disarmingly simple reason, really: if you have twice as many chromosomes you need bigger cells in which to keep them.
Genome duplication is a common phenomenon in the history of flowering plants.
Many crops – like potatoes, tobacco and coffee – are polyploids.
But that duplication typically takes place far back in evolutionary history. For mimulus guttatus it happened in what is, on the evolutionary timescale, the blink of an eye: well under 200 years ago.
Dr Vallejo-Marin, who specialises in the evolution of plants, says:
“Evolution is often thought to be a slow process taking thousands or millions of years.”
“Yet we show that a major evolutionary step can occur in less than a couple of hundred years.”
The new plant was discovered by chance during fieldwork near Quarff, south of Lerwick.
The team measured the size of the plant’s genome and surveyed 30 populations of monkeyflowers from Shetland and elsewhere in the United Kingdom.
The plants were then grown under controlled conditions and their characteristics were measured to compare the effect of their duplicated genome.
The researchers carried out genetic analyses to investigate the relationship between the new plant and other similar populations in Shetland.
Genome duplication seems to be particularly common in hybrids between different species. But the new plant has doubled its genome without hybridisation – it has the same species as both its father and mother.
The team says a new polyploid plant like this represents an opportunity to investigate the early stages of an important evolutionary process.
Dr Vallejo-Marin says:
“Human activities are transporting all sorts of animal and plant species well beyond their native habitats.”
“This raises the possibility that non-native species may increasingly participate in major biological processes, including the formation of new types of plants and animals.”
The paper “Recent autopolyploidisation in a wild population of Mimulus guttatus (phrymaceae)” has been published in the Botanical Journal of the Linnean Society.