Love is in the water

by Janie Jones

It occurred to me that I forgot to share a very important update in the wake of Constitution Day.

I’m sorry if you’ve all been on tenterhooks with anticipation to know the outcome of my fish experiment.

So last week Thursday I got to genetics lab and found that Verda and Rudy didn’t spawn.

*sad face*

But apparently odds for a single couple spawning aren’t that stellar.  Out of all the different classes doing this project there were 60 something “fish couples” and only 12 produced baby fish.

I ended up having a pretty cool Genetics lab anyway.  We got to look at the baby fish (called larva, apparently) under these special microscopes.  You can see fish larva with the naked eye, but they are super tiny, think smaller than the size of an eyelash.  Mostly they are clear, but you can see some of their skeletal and muscular system which give that appearance of a very fine, small, black eyelash.  However, under the microscope you can see all the details.  You could see their eyes and fins move and you could see their gills flap.  If you were looking at a fish that had inherited the fluorescent genes, you could put on a special light and see the colors glow.  It was cool.

As my couple didn’t couple, I had to pick from some fish belonging to other students.  So I picked a purple to wild type cross to look at under the scope.  I reasoned that, because it is thought that the purple fish are actually that color because they get a red transgene and a blue transgene that sort of combine to form an intermediate color (thinking back to your color wheel from your art class days, red+blue=purple, right?),  if you cross a purple fish with a natural wild type fish, in theory, you shouldn’t get any purple fish because, due to the nature of genetic inheritance, your purple parent fish can only pass on one blue gene or one red gene per offspring.  For the same reason you won’t expect any wild type fish, because the transgene is believed to be dominant over the wild type, or normal color, gene.  So every egg gets one one wild type gene from the wild type parent and one color transgene from the purple parent, either red or blue, that will mask or dominate over the wild type gene.

This couple only produced three babies.  But seeing as we were looking at tiny larva, they all looked the same at first.  While it is not impossible to end up with three that all look the same, I couldn’t see any real color at all.  I was hoping to find a nice combination of red and blue fish.

And, guess what?  There was one red, one blue and one wild type.

An exciting curiosity.  While I got both colors, I also got an unexpected wild type.

It seems as though we have to write a little research paper about our fish experiment.  Because this couple only had three babies, it’s not really enough to judge accurately what inheritance patterns are present.  And, there is that errant wild type larva.  It turns out that the professor had two tanks of other purple to wild type crosses she spawned the night before, she’s putting them aside for me and I can use those progeny, too, which will hopefully give me a larger pool of progeny to base a paper on.

Biology is so cool.  This is why I put up with all the school crap.


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