Examples given by Li et al.do not prove models IV and V of independent transcription of snoRNA genes. (a) Models IV and V with the corresponding examples from . (b) Screenshots of UCSC Genome Browser for the loci in panel (a) demonstrating that all snoRNA genes are localized within introns of host genes (EST track). Genomic coordinates for the March 2006 human reference sequence (NCBI Build 36.1) are given.
Makarova and Kramerov BMC Genomics 2011 12:543 doi:10.1186/1471-2164-12-543