Not Optimistic About the Genetic TA ...

I've been going to my genetics lecture for almost 2 weeks. We're mostly dealing with math now - basically, how to calculate the number of offspring with specific traits or hereditary diseases. Not something that I exactly expected when I chose the course. But well, it can be interesting to know the math behind some biological phenomena.

We learned the Bayes' Theorem. It is used for, for example, calculating the chance of a couple getting a second child with a certain genetic disease, given that their first child doesn't have the disease. The formula for the Bayes' is a bit complicated and it gets confusing sometimes, so I looked forward to discuss with my genetics TA.

My genetic TA spent our first discussion section on only one problem, because she basically did it wrong! A few students (including me) kept arguing with her about this question. I think she made all of us confused. I believe we should apply Bayes' Theorem to the particular question, the TA however used the wrong formula, used the wrong number, and ... got the right answer! In addition, she used the autosomal gene pedigree for this question regarding an X-linked disease. I don't know how that worked, but she thought it was the "shortcut" to the Bayes. I was certainly unhappy that my TA made such a big mistake the first time we met ...