We are going to get some readers upset. Not that we matter much in the world but this is our opinion. Nature has published a Paper on the proximal origin of Sars-CoV-2. We think the paper is misleading. The authors propose that there are 2 reasons for believing that Sars-CoV-2 is not genetically engineered. The first reason is that the receptor-binding domain of the spike protein is not optimal. Well, whatever does optimal mean? They do not explain. But they go on and say that the receptor-binding domain has high affinity for the human ACE2 receptor. Ok, this is high enough affinity to cripple Northern Italy and probably Iran's healthcare system so, what more do you need?
The author's do comment is that the Sars-CoV-2 spike protein does not resemble any known spike protein in the NCBI GenBank database related to this family of coronavirus. They discuss the furin cleavage site of the spike protein (S1-S2 junction) and note that this particular cleavage site is not found in other B'betacoronaviruses. So, they note that this is a novelty for this family of coronaviruses. This particular site was noted in India for resembling a segment of the Human Immunodeficiency Virus.
The author's second argument or reason is that the Sars-Cov-2 virus backbone does not resemble any other backbone in the NCBI GenBank database. Their reasoning is that if someone were to manufacture this virus they would start off with an already known virus that has the good fortune of showing up in a public database. Keep in mind that while many of the viruses in the database were categorized recently the came from old material dating back 20-years to Sars. Who knows what those backbones would look like after 20-years of mutation?
In their conclusion, they go on to state, " it is currently impossible to prove or disprove the other theories of its origin described here".
We call BS. This is merely expert conjecture and not science. We will let you be the judge. For you conspiracy theorists, The Open Society Foundations have contributed to the Wellcome Trust.