id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-261662-d0tg9i90	Andres, Cristina	Naturally occurring SARS-CoV-2 gene deletions close to the spike S1/S2 cleavage site in the viral quasispecies of COVID19 patients	2020-06-08		.txt	text/plain	4673	214	52	title: Naturally occurring SARS-CoV-2 gene deletions close to the spike S1/S2 cleavage site in the viral quasispecies of COVID19 patients Here, we deep-sequenced the complete SARS-CoV-2 S gene from 18 patients (10 with mild and 8 with severe COVID-19), and found that the virus accumulates deletions upstream and very close to the S1/S2 cleavage site, generating a frameshift with appearance of a stop codon. Because of the importance of the S protein, we carried out a deep-sequencing study of the S gene in upper respiratory tract samples from 18 patients with mild or severe SARS-CoV-2 disease. The fact that the truncated S protein was present in only a low percentage of the entire viral quasispecies suggests that natural selection may have designed a favorable equilibrium in which a limited number of deleted virions are generated to balance virus production with infection of new cells during disease progression.	./cache/cord-261662-d0tg9i90.txt	./txt/cord-261662-d0tg9i90.txt