Step I Genetics and the pedigrees

[Cardiochick]

Advertisement - Members don't see this ad

Hi there
Having a hard time dealing with the pedigrees and differentiating the inheritance modes..
Any advice on best way to tackle this topic or any explanations would be awesome.
Thank ahead 🙂

 

[seminoma]

Hi there
Having a hard time dealing with the pedigrees and differentiating the inheritance modes..
Any advice on best way to tackle this topic or any explanations would be awesome.
Thank ahead 🙂

Draw punnet squares until it makes sense. That's what I did throughout genetics in school and now it isn't an issue.

Edit: Or if I misinterpreted your post and you're talking about determining the inheritance pattern given a pedigree, then you should just memorize 1-2 things about each mode of inheritance. Those 1-2 things are usually all you need.

1. X-linked: no male-to-male transmission.
2. XD: father-to-daughter transmission 100%, mother-to-son 50%, mother-to-daughter 50%.
3. XR: Males >>> females.

4. AD: every generation, male/female 1/1.

5. AR: skips generations. Usually only 1 generation affected unless the pedigree is huge.

Mitochondrial: All children of affected females.

For 1-5 draw punnet squares so the rules make sense. Makes it easier to remember. And, if you forget, you just need to draw a quick punnet square.

 

[Cardiochick]

I will definitely memorize those points and have them in mind before determining any mode of inheritance.
Thanks for the input 🙂