Sunday 27 September 2015

What shall we call it?

Scientists are big into naming of parts. If everyone agrees on the name then there can be no mistake about what's being studied. With my multinational readership (Привіт Київ, Gruß Wien, Bonjour La France) I try to be religious about including the Linnean binomer of all the organisms I mention.  There is going to be confusion if I mention "chestnut" because it could be Aesculus hippocastanum or Castanea sativa and only one of them is edible. The toxic one is not that poisonous, and apparently the flower has been adopted to represent the city of Kiev [Привіт Київ]. If it's important for species, it's also vital for genes, which have to be named unambiguously; to replicate molecular experiments for starters. We are collectively much worse = inconsistent about naming genes.  But some areas of biology have been particularly well disciplined and short on ego and one of those is the genetics of the fruitfly Drosophila melanogaster and its relatives.  Flybase imposes a necessary and desirable authority and order on what genes are called and how the data about each gene is presented. It's clear that geneticists, since Thomas Hunt Morgan and his students 100 years ago, have had a lot of fun being clever when naming genes.  Actually, what they have effectively been doing, especially in the early days, is naming mutations in genes - all fruit flies look the same until there has been a mutation at one spot in their DNA that changes the looks or behaviour or development of the fly.

The early genes were identified by something rather what-it-says-on-the-tin obvious: 
  • white w (eye colour); 
  • eyeless ey; (my dog's fly's got no nose eyes)
  • Antennapedia Antp (has legs growing out the top of the head).
Then there were flies that seemed to be less responsive or slower to learn than normal.  I'm not sure which came first but a whole group of 'intelligence' genes were named:
  • dunce dnc (a simpleton)
  • cabbage cab (cabbage is British slang for one supposed to be mentally handicapped)
  • turnip tur (by extension from cab)
  • rutabaga rut (also by extension from cab)
There is a developmental gene which is vital for differentiating the top and bottom of the fly embryo. It also functions as an immune recognition receptor to detect pathogens and start an effective response against them. The equivalent genes in mammals have retained the immune function and seem to be differentially expressed in different parts of the embryo. The first gene in the family was called
  • toll Tl (because Christiane Nüsslein-Volhard was so astounded when she saw the first mutant that she cried "Das ist ja toll!")
  • 18-wheeler 18w (a protein with a similar structure but different function; mutants supposed to look like the tarpaulin over a truck)
Other hilarious ha ha ha ha coinages include:
  • ken-and-barbie ken (because mutant flies have no external genitalia)
  • abnormal spindle asp (has trouble with cell division)
  • cleopatra cleo (lethal if asp <above> is also present)
  • tinman tin (no heart)
  • nanos nos (from νᾶνος = dwarf, as in nanometer)
  • smaug smg (suppresses nanos <above>) 
  • lush lush (inordinately attracted to the smell of ethanol)
  • methuselah mth (remarkably long-lived) 
Parallel sources: io9itsOK2bSmart; bitesize; curioustaxonomy.  It's a bit sad really, all of us re-churning essentially the same information.

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