A moron (in bacteriophage biology) is a DNA element inserted between a pair of genes in one phage genome when the genes of this same pair are adjacent in a related phage genome.hmmm.. yaaa... Not so helpful, ASM. Luckily, Bossmans lecture on morons in class this week was much clearer.
'Morons' are genes that bacteriophages carry around which are unnecessary for the virus, but helpful for the host bacteria.
This doesnt make sense at first, because when we think of viruses (especially bacteriophages) we think of infection, making lots of baby viruses, and BOOM!!-- cell explodes and all the viruses are released. Why would it care if the bacteria is comfy as its exploding?
Well, thats not really what happens with phages. They infect a cell, insert themselves into the bacterias genome, and chill. They just sorta hang out until some stressor tells the virus its time to jump ship. Think about it-- who is more fit, a virus that blows up its host and produces a thousand progeny who might/might not find another host cell, or a virus that sits silently in a genome, getting passed down through the generations laterally for a million years? The latter! But while hiding in someone elses cell is a good idea, silent phages have the same problem as plasmids-- How do you convince a bacteria to keep you around when you are genetic dead weight?
Morons help the bacteria survive by being novel genes that make the bacteria more competitive with its peers in an old niche, or giving the bacteria the ability to exploit a new niche. Morons are kind of hard for us to appreciate... Like the MORON that encodes Type III secretion effectors that make you poop when youre colonized by Salmonella or the MORON toxins that make you poop when youre infected with Cholera or the MORON toxins that make you poop when you eat spinach sprinkled with E. Coli... but theyre actually a really cool evolutionary story, demonstrating the co-evolution of bacteria and their phages over time! Bacteria even have 'endogenous phages' like we have endogenous retroviruses!
I was rather pouty about getting my PhD in microbiology because of all of the associated 'bacteria based' classes I would have to take (Ive never taken an intro micro class-- cocci-wha?), but this stuff is friggen fun!