Freaky Mutant Mouse Steals Genes to Resist Poison
Baku, August 10 (AZERTAC). The European house mouse inherited a chuck of genes from the Algerian mouse in one of the first examples of genes spreading between species of mammals.
Poison-resistant mice have been giving homeowners throughout Germany and Spain increased trouble in recent years. New research indicates that some of these mutant mice developed their immunity in a surprising way: by stealing it from another species.
Poison resistance usually evolves as a result of changes to one letter, or chemical base, of the genetic code. In contrast, these freak mice, a mutant form of the European house mouse, inherited a whole chunk of genes from Algerian mice, a species they shouldn’t have been able to breed with. And the process is still continuing.
"For animals, we did not know that there seems to be another pathway how you can evolve, by adopting a gene from another species and incorporating it into your own DNA," said study researcher Michael Kohn of Rice University. "In microbes it`s quite well understood"— in plants, too — "but I don't think anyone could have thought this type of thing could happen in animals."
By sequencing the genes of the two species of mice, and the resistant strains of the European house mouse, the researchers discovered that two different types of mutation provide the same resistance.
Both types of genetic changes make the mice resistant to a type of poison that thins their blood by incapacitating a protein called vkorc1. This protein normally leads to the activation of vitamin K, enabling blood clotting, but it doesn`t when the poison is present. With the mutation, though, vkorc1 can escape the poison's incapacitating effects.
The researchers discovered that the vkorc1 gene from some of the European house mice was more similar to that of the Algerian mice than to the other resistant European strain or even to normal, non-resistant European mice.
The researchers think the Algerian mice developed this mutation because of their vitamin K-deficient diet, though they aren't sure how. It entered the European house mouse population when the two species mated several generations ago. The two species are evolutionarily separated by over 1.5 million years, so most hybrids of the two species don't survive or can't produce offspring.
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