> The team found that the L type was most prevalent in the early stages of the outbreak in Wuhan, China. After early January, the frequency of L type started to decrease.
“Human intervention may have placed more severe selective pressure on the L type, which might be more aggressive and spread more quickly. On the other hand, the S type, which is evolutionarily older and less aggressive, might have increased in relative frequency due to relatively weaker selective pressure,” the study authors explained.