I know nothing about DNA or viruses. There have been claims that the virus was manipulated in the Wuhan lab to make it more infective to humans but I've never seen anything to convince me of that.
It still doesn't discount the lab leak theory. Scientists in Wuhan were studying coronaviruses in that lab. Suddenly, there was an outbreak of a coronavirus in Wuhan. Coincidence?
The first thoughts of China's leading expert on coronaviruses when she heard about the outbreak were:
“I wondered if [the municipal health authority] got it wrong,” she says. “I had never expected this kind of thing to happen in Wuhan, in central China.” Her studies had shown that the southern, subtropical provinces of Guangdong, Guangxi and Yunnan have the greatest risk of coronaviruses jumping to humans from animals—particularly bats, a known reservoir. If coronaviruses were the culprit, she remembers thinking, “Could they have come from our lab?”
https://www.scientificamerican.com/...wn-viruses-from-sars-to-the-new-coronavirus1/