“Micro homology”. Wut?
I ranted in a previous post about the use of homology as a quantitative term, rather than a qualitative term. Ben Blackburne commented on that post introducing me to “micro homology”, a term I did not know existed. I ignored its existence, until I heard it spoken yesterday at a talk, which sort of rubbed me the wrong way. Going back to my office to chill, I discovered there are 152 papers indexed in PubMed that use that term in their abstract or title. Not a good way to chill… here we go again: misusing “homology” by overselling it. Apparently microhomology is used to indicate an identity of a short nucleotide sequences in two non-complementary DNA strands. This identity may facilitate strand annealing constructions of chromosomal breakpoints such as the proposed Microhomology-Mediated Break-Induced Replication or microhomology-mediated end joining for DNA repair. There should be a term for this phenomenon, but why use “microhomology“? The use of “homology” implies that the short identical sequences originated from a common ancestor. “Micro” would mean short region from otherwise homologous sequences. This is possibly derived from “homologous recombination“, where, indeed, homologous sequences are involved. But in the microhomology case, it may not be so. Also, even if the identity is between short subsequences of otherwise homologous sequences, “microhomology” is somewhat of a confusing term, as it implies a quantitative relationship. Why not simply use “microidentity” as a drop-in replacement? (Heh: non-homologous replacement).
Of course nothing will change, since I am too late in the game, no one listens to me anyway and I do not see the six readers of this blog rallying to eradicate microhomology.
No I am not bitter. Mild and bitter perhaps, but only after 5 o’clock.