Hello! Thanks for your question!

So in terms of topics on the MCAT, some basic genetics is included. This includes knowing about things like DNA replication, transcription, and translation in eukaryotes and prokaryotes; plasmids in prokaryotes; doing Punnett squares to determine inheritance; pedigrees; and more. There is definitely more of a focus on transmission of genetic material than the actual calculations of probability and inheritance. Taking the class before the MCAT certainly would not hurt, but it probably is not necessary if you have learned genetics in your college-level biology class. On the AAMC website itself, it cites that the classes many students take prior to the exam (in terms of the biology section) include: first-semester biochemistry, two-semester sequence of introductory biology, two-semester sequence of general chemistry, and two-semester sequence of organic chemistry.

Here is a link to the bio content on the exam from the AAMC website: https://aamc-orange.global.ssl.fastly.net/production/media/filer_public/24/19/2419a765-fc49-466b-bcf8-b6470a8ff273/mcat-bb-content-outline.pdf. I suggest scrolling through it to check out the other topics included in this section!

– Kiran