I realize that I missed an opportunity, though! A week or so ago I was teaching my cell biology class about cell cycle regulation, and I was all about retinoblastoma, Rb, the gene product that acts as a regulator of the cell cycle — the cell will not proceed to the DNA synthesis phase unless Rb is deactivated by phosphorylation first. And then this week I was talking about the evolution of multicellularity, so I showed them unicellular algae like Chlamydomonas, and constitutive colonial protists like choanoflagellates, and of course I told them all about Volvox…but I failed to connect the two.
Now I read about the complexities of cell division in Chlamydomonas which could have played a role in the evolution of multicellularity, and from there I learn that differences in cell cycle can be traced to slight modifications of a few genes (no new genes required), in particular…Rb!
I wonder if the students would complain if we wound the class back to early November and started over? Probably.
Although today is a weird class day — it’s the day before Thanksgiving break, and I know from past experience that attendance will be very, very poor as students skip out to go home for vacation a day early; I also polled the class on Monday and learned that only about a quarter will show up (isn’t it nice that they’re honest about it?) I’m bribing them by promising pizza in class, but I’ve also told them it’ll just be a review/Q&A day. Maybe we can just sit down and have a conversation about science over pizza.