My genetics students are learning a bit about sex linkage and modes of inheritance, so I’ve got them thinking about an entirely hypothetic problem outside of class. I’ll be interested to hear their explanations, but this is the kind of problem that would drive me nuts to try and grade. Let’s see how you all do with it.
In Guardians of the Galaxy, the assassin Gamora is bright green. Her sister Nebula is blue.
a. Invent a genetics of skin color in her species, the Zehoberei, that explains their differences in color, using an autosomal gene and modeling it after human patterns of inheritance, and use it to predict the skin color of their parents. (Note: Thanos is purple, but he’s a different species and is their adoptive father.)
b. Now assume the trait is X-linked. Does it change your prediction for their parents? What color(s) would a hypothetical brother be?
c. A new twist: in Zehobereians, females are the heterogametic sex. What does this do to your model?
The fun part is (a), which could have all kinds of possible explanations (that’s why I couldn’t put it on an exam, the range of possibilities is huge), with the one constraint being that it has to be autosomal. I want to see some dueling discussions about how it would work, brought down to earth by the need to make a prediction about the parents.
Then (b) changes the assumptions, and forces their model to change, and (c) flips it around some more. I don’t want to grade this kind of question, I just want to see how their brains logic their way around it. It should be fun. I hope.
I also had some ideas about the inheritance of color in Minecraft sheep, but decided that was just too weird. Blending inheritance + acquired characters? Heretical. Not very instructive about Earthly rules of genetics.
Of course, it may all be moot because attendance in all of my classes is declining this semester — only half the students showed up today! I don’t know if it’s pandemic fears (no diagnosed cases in Morris), the imminence of Spring Break, or that I’m just horribly boring.