Here’s todays headscratcher from Phys.Org.
It appears that to contrive a “mature” micro-RNA (mi-RNA), involved in gene regulation, the cell requires hundreds of kilobases of sequence. How odd. “Mature” mi-RNA’s are ~22 bases in length, and hundreds of thousand of nucleotide bases are needed (of primary-mi-RNA) to effect this ~22-nucleotide regulatory element?
Here’s what they say:
MicroRNAs are short noncoding RNAs that play critical roles in regulating gene expression in normal physiology and disease. . . .
Although mature miRNAs are only ~22 nucleotides, their transcripts are up to hundreds of kilobases long. Primary miRNA transcripts, or pri-miRNAs, are quickly processed into mature miRNAs from hairpin structures located in the exons or introns of pri-miRNA transcripts.
One remarkable feature of primary miRNAs is their extreme length, even in cases where they function only to produce a single ~22 nucleotide miRNA,” said Joshua Mendell, corresponding author of the study. “Although it seems wasteful to produce such long RNAs, most of which will be immediately degraded, this organization may have arisen to allow complex mechanisms of regulation of the encoded miRNA.
As usual, they’re “surprised” about their findings (very likely they are ‘surprised’ because they weren’t expecting things to turn out so complex). And, as usual, the pro forma reaching out to “evolution” as the explanatory mechanism, when, in fact, no explanation is given at all: . . . this organization may have arisen to allow complex mechanism of regulation of the encoded mi-RNA.”
It may have; but, it may have not. Is this scientist willing to consider this other possibility, or is it simply an article of faith that “evolution-did-it”? One wonders.