Practice question

mRNA-seq specifically enriches and sequences messenger RNAs that encode proteins. Total cellular RNA comprises predominantly ribosomal RNA and transfer RNA, with small nuclear RNA and other species. Messenger RNA typically contains poly-A tail and represents only 1-5 percent of total RNA but carries coding information. Protocols using oligo-dT beads selectively capture polyadenylated mRNA, allowing study of protein-coding expression levels, splice variants and untranslated regions. Sequencing rRNA, tRNA or snRNA would require distinct rRNA depletion or small RNA protocols, not standard mRNA-seq targeting coding transcripts.