Assertion: dna's sequence | /r/HasProperty | intron
Facets:
Source sentences:
text: Cech showed that a noncoding sequence (intron) in the small subunit rRNA of protozoans, which had to be removed before the rRNA was functional, can excise itself from a much longer precursor RNA molecule and rejoin the two ends in an autocatalytic reaction.
text: The sequences that are expressed in protein are called exons, and the interspersed sequences are called introns.