Chuck Bednar for redOrbit.com – @BednarChuck
The discovery of a new species of monkeyflower in Scotland three years ago has unexpectedly led to a second finding – one that could provide new insight into the evolutionary process.
University of Stirling evolutionary biologist Dr. Mario Vallejo-Marin, who was responsible for first locating the new species on the banks of a stream in South Lanarkshire in 2012, decided to go on an expedition to the Orkney Islands off the north coast of Scotland two years later.
As Dr. Vallejo-Marin, a senior lecturer in the School of Natural Sciences, explained in a statement, “Orkney was a missing region which hadn’t been sampled. There were different varieties of monkey flower on the island, but when we spotted this population I knew it was unusual as after looking at hundreds of plants, you get to recognize the subtle differences.”
“Usually a species forms once in a particular location then spreads to other regions,” he added. “In this case, the opposite has occurred as the same species has evolved multiple times in different places. It shows that when the conditions are right, the origin of species is a repeatable phenomenon.”
Doubling down on chromosomes to form a hybrid species
The monkeyflower species, which Dr. Vallejo-Marin called Mimulus peregrinus (a name which means “the foreigner”) because it originated from two different invasive species, was described as a rare find because these types of hybrid types are normally unable to reproduce.
In this case, however, the flower doubled the amount of DNA contained within its cells, evolving to create a new species through a process known as polyploidisation. In polyploidisation, a plant that normally has two sets of chromosomes winds up having four, allowing different interspecies breeding to occur. It is through this process that wheat, cotton, and tobacco originated.
Dr. Vallejo-Marin, who published his findings in the journal Evolution, said that is impossible to determine if Mimulus peregrinus originated in the northern or southern part of Scotland, but that the discovery of this “very young species” has “allowed us to study evolution as it happens.”
“We only know of a handful of other plant species as young as Mimulus peregrinus and so in this respect it is like looking at the big bang in the first milliseconds of its occurrence,” he explained, adding that the new type of monkeyflower “is an example of how some branches can come back together again and spawn new species that are in part the combination of their ancestors.”
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