I assume by "fragment" they mean "contig"[0]. This statement only has meaning if this particular contig is: a) found at WIV b) not found in the wild (to our kno

I assume by "fragment" they mean "contig"[0]. This statement only has meaning if this particular contig is: a) found at WIV b) not found in the wild (to our knowledge, which we would expect to be incomplete) c) unlikely to have evolved in the wild from SARS-CoV-1 over the past 10 years. My reading of this sentence indicates they're saying a), but they don't mention b) or c). A good biologist wouldn't bother mentioning this type of thing unless they had good evidence for b) and c), but the sources are uncited and there's no details here. So I really wouldn't take anything away from this. [0] https://en.wikipedia.org/wiki/Contig https://en.wikipedia.org/wiki/Contig