The genetic mutation that ruins orange-coloured fish sex lives

Washington, Sept 29 (ANI): Researchers from University of Konstanz, Germany and the University of Tokyo have found a genetic mutation that gives medaka fish its grey colour, rendering them less attractive to the colourful members of the opposite sex.

The Japanese Killifish is commonly found in Southeast Asia in wide range of colours like brown, orange and grey.

The research team led by Shoji Fukamachi studied the effects of alterations in a colour-determining gene on mating preferences of the fish.

The greys, however, need not be completely despondent at these findings, as the study also showed that they were preferentially selective for each other.

"We observed that the grey medaka were often rejected in favour of their brown or orange rivals," said Fukamachi.

"This is the first demonstration of a single gene that can change both secondary sexual characteristics and mating preferences," the expert added.

Orange colour in medaka is determined by the presence of pigmented structures known as xanthophores, and these are reduced in the grey fish carrying the mutant gene.

By over-expressing this same gene, the researchers created super attractive bright orange medaka that induced hyperactivity in similarly engineered members of the opposite sex while other potential mates were ignored almost completely.

"Thus, the present finding of the xanthophore-dependent mate choice enables many ingenious experiments to be designed in this and other fish species," said Fukamachi.

"This discovery should further facilitate molecular dissection/manipulation of visual-based mate choice," Fukamachi added.

The study appears in open access journal BMC Biology. (ANI)