When the going gets tough for agricultural plants, for instance, the number of transposable elements seems to decline.

ECONOMIST: Truly selfish genes

But Dr Nuzhdin reckons that it may hold a clue to the proliferation of different transposable elements in other organisms.

ECONOMIST: Truly selfish genes

Dr Nuzhdin thinks that the main reason why copia does not proliferate like this in wild populations is that natural selection keeps these transposable elements in check.

ECONOMIST: Truly selfish genes

"My dream is that these transposable elements will be tools that we can use to make the mouse more like the fruit fly, " says David Largaespada, a researcher at the University of Minnesota.

FORBES: Glowing Mice From China And Other Oddities

In collaboration with Elena Pasyukova at the Institute of Molecular Genetics, in Moscow, and Trudy Mackay of North Carolina State University at Raleigh, he has been studying a transposable element known as copia.

ECONOMIST: Truly selfish genes

And, while copia and its close relatives are not normally found in anything with more backbone than a reptile, its activities may hold clues about the behaviour of some of the other, more complicated, transposable elements that are found in those more complicated vertebrates, the mammals and the birds.

ECONOMIST: Truly selfish genes