Glad that somebody pointed that out. IMO, if somebody wants to get a quick overview of genetics, their time would be much better spent watching lectures 4-7 from Sapolsky's Human Behavioural Biology lectures [1]. In those 4 lectures Sapolsky's explores contradicting theories about (among other things) the unit of selection and gradualism. Highly recommend the whole series.

[1] https://www.youtube.com/watch?v=_dRXA1_e30o&list=PL150326949...