You’d think that losing 25 percent of your genes would be a big problem for survival. But not for red algae, including the seaweed used to wrap sushi. An ancestor of red algae lost about a quarter of its genes roughly one billion years ago, but the algae still became dominant in near-shore coastal areas around the world, according to Rutgers University–New Brunswick Professor Debashish Bhattacharya, who co-authored a study in the journal Nature Communications.