Gene switches help perch adapt to dark bog lakes

Perch in dark bog lakes adapt mainly through changes in gene regulation, rather than by acquiring new genes, a study reported by ERR has found.

Researchers from Estonia, Lithuania and Sweden compared gene regulation in perch from clear-water lakes and dark, humic-rich lakes. They mapped more than 76,000 genomic regions in the fish’s eye, liver and spleen tissues where regulatory proteins can bind.

Although differences between tissues were substantial, gene regulation in fish from dark- and clear-water lakes differed by only about 0.3 percent. One example was a regulatory switch inside the TCHH gene, which is linked to skin and tissue development. The switch was active in the spleen of perch living in dark water but not in the fish from clear-water lakes. The researchers said it may help the fish cope with that environment.

The findings suggest that adaptation does not always require changes to the structure of proteins. Changes in gene-regulating regions can help perch adjust their vision, metabolism and immune systems to the conditions of their habitat. The study found such changes more often than usual in regions that switch genes on and off.

The study was published in Molecular Ecology.