GP was referring to the “L” and “S” strain theory I believe, which was debunked. The paper you linked is new, and the “more transmissible” property they discuss may just be the “founder effect” at work. It needs more research.
It's difficult to know what user coldtea had in mind. He could have meant the L/S (debunked) theory, or the theory that some strains in Iceland are ineffective [1].
In any case, there are multiple credible sources that some of the mutations of the SARS-CoV-2 have a meaningful effect. In which case the claim of this article that "there's only one strain" may be technically correct (based on some obscure scientific definition), but completely misguiding as far as the general public is concerned.
> the theory that some strains in Iceland are ineffective
I don't see any support at all for that theory though. It is also known that "X show no symptoms" could mean many things, depending who says it and when, and certainly doesn't prove anything alone, only in context, compared to something else, and only when comparison is fair.
For example, from many old news, those "with no symptoms" eventually had the symptoms, it was just that the tests were positive before they developed the symptoms. Second, it is now known that the probability of "having" symptoms is very dependent on the age of the person.
In any case, there are multiple credible sources that some of the mutations of the SARS-CoV-2 have a meaningful effect. In which case the claim of this article that "there's only one strain" may be technically correct (based on some obscure scientific definition), but completely misguiding as far as the general public is concerned.
[1] https://english.alarabiya.net/en/features/2020/03/25/Coronav...