Carp demonstrate rapid de-evolution to get their scales back

August 24, 2016 by Bob Yirka 

(Phys.org)—A team of researchers with members from France, Hungary and Madagascar has found that a type of carp bred to have fewer scales and subsequently released into the wild in Madagascar a century ago has devolved to get its scales back. In their paper published in Proceedings of the Royal Society B, the team describes how they collected large numbers of specimens to study their scales and to look at their DNA and what they found.

Approximately a century ago, a group of monks in Europe embarked on a mission to make carp less work to prepare for eating—they bred them to have fewer and fewer scales over successive generations and were so successful that the fish became known as mirror carp because of their newly reflective properties. Then, in 1912, a group of Europeans released mirror carp into the wild in Madagascar as a food source for people living there—until that time, there were no carp present at all. The program was considered a success as the fish flourished in the new environment. It did not take long for the breeding process to begin reversing itself, however—as early as 1950, people in the area were reporting that the carp were becoming scalier. In this new effort, the researchers sought to better understand the evolutionary process that the fish have been undergoing over the course of the past century.

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