A sestina, or sextain, is a poem comprised of six stanzas containing six lines each. These six-by-six stanzas are followed by a shorter (3-line) final stanza known as an envoi. This gives the sestina a total of 39 lines (6 * 6 + 3 = 39).
1 A nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and possibly a truncated, and often nonfunctional protein product.
mRNA half-lives reveal its lifetimes(stability), which can be affected by many factors, e.g. mRNA sequences, the mRNA's primary and secondary structure, like ploy(A) tail and steam loop, determined by its sequence, can alter mRNA's accessibility to enzymes.