The evolutionary arms race can lead to similar traits, but genes develop differently. Researchers at the Max Planck Institute for Evolutionary Biology in Plön, Germany, conducted extensive tests on genetically identical Choralla variabilis algae distributed on different cell cultures. The development was observed for 90 days, with three populations infected with the Chlorovirus PBCV-1. The algae and parasites developed new attack and defense tools in an evolutionary arms race, with the value and parasite undergoing a kind of co-evolution. The tests showed that resistant cells had duplicated a specific region of their genome, reducing the cost for algae when facing pathogens.
The researchers found that while the evolutionary arms race can lead to similar traits, genes develop differently. When the single-celled algae Choralla variabilis was combined with the deadly Chlorovirus, the result was always the same: collapse or recolonization. The algae were mostly resistant to the virus, and the evolution could be similar under the same starting conditions. However, the algae carried different mutations with each repetition. The researchers observed that a population alone could reproduce until it reached maximum density, but when co-evolving with the virus, the population usually collapsed after 15 days. The virus population, on the other hand, increased significantly.
After 45 days, the parasite and host had perfected their attack and defense measures, with neither having an advantage. The algae were even resistant to viruses, with the tests showing that resistant cells had duplicated a specific region of their genome. While the duplication did not make the cells directly virus-resistant, it reduced the cost for algae when facing pathogens. The tests showed that evolution could produce the same resistances or traits under the same conditions.
