Great podcast by Sean Carroll, who interviews William Ratcliff who studies experimental evolution of multicellularity in yeast.
They cover such interesting topics and questions as:
Is it just re-activation of an old pathway for multicellularity in yeast?
Do they show true differentiation?
What selective pressures drives multicellularity to evolve?
Do the researchers make the mutations happen, or select on specific mutant traits like in selective breeding, or do the mutations just occur and the environment selects on phenotypes?
How does environmental factors like oxygen concentration play into selection for multicellularity?
How does physics play into the evolution of multicellularity and how does it affect things like shape and size?
The history of multicellularity and the origin of eukaryotes.
All topics that have been discussed here before, that they are studying experimentally.