Table 1.

Sample of question and answers in COVID-19 domain.

Question	What is the origin of COVID 19?
Expected nuggets	’spillover’, ’positive selection pressure’, ’the species barrier’, ’potential mutations’, ’genetic recombination’, ’animal-to-human transmission’, ’bat reservoirs’, ’Codon usage bias’, ’ancestral haplotypes’, ’bat coronavirus genome’, ’zoonotic origin’, ’seafood wholesale market in Wuhan’, ’evolutionary constraints’, ’pangolins’, ’interspecies transmission’, ’betacoronaviruses’, ’viral fitness’, ’molecular evolution’, ’Chinese province of Hubei’, ’Mammal species’, ’Bats’, ’virus adapation’, ’species of origin’, ’emergence’
Retrieved contexts and text spans
1	It is improbable that SARS-CoV-2 emerged through laboratory manipulation of a related SARS-CoV-like coronavirus. As noted above, the RBD of SARS-CoV-2 is optimized for binding to human ACE2 with an efficient solution different from those previously predicted.
2	Furthermore, if genetic manipulation had been performed, one of the several reverse-genetic systems available for betacoronaviruses would probably have been used.
3	However, the genetic data irrefutably show that SARS-CoV-2 is not derived from any previously used virus backbone.
4	Instead, we propose two scenarios that can plausibly explain the origin of SARS-CoV-2: (i) natural selection in an animal host before zoonotic transfer; and (ii) natural selection in humans following zoonotic transfer.