A. The haplotype networks of SARS-CoV-2 viruses. Blue represents the L type, and red is the S type. The orange arrow indicates that the L type evolved from the S type.
B. Evolution of the L and S types of SARS-CoV-2 viruses.

The coronavirus has evolved into two major types, with differing transmission rates and geographical distribution, according to a study published in the National Science Review yesterday.

A group of Chinese scientists analysed 103 coronavirus genomes and identified mutations in 149 sites across the strains.

They found that one type, which they called the L type, was more prevalent than the other, the S type, meaning it was more infectious. They also found that the L type had evolved from the S type, and that the L type was far more widespread before January 7 and in Wuhan, ground zero of the outbreak.

Human actions soon after the outbreak was discovered in December may have changed the abundance of each type, the report said, citing the Chinese central and local governments’ drastic containment measures including lockdowns of cities, which it said may have curbed the spread of the L type.

The researchers said follow-up studies were needed to form a better understanding of the virus’ evolution and spread.

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