Lecture 12: Family based association tests

Question 1

What is the trio design?

Answer 1

Parents and one offspring to test association.

Parent genotype known - child is affected

Question 2

What forms the basis of the trio design?

Answer 2

Testing if the inheritance pattern is different from mendelian inheritance - if it is the marker is associated with the phenotype.

Question 3

Idea behind transmission disequilibrium test:

Answer 3

We look only at heterzygotic parents - the alleles that are inherited should have prob. 0.5 if they are in LE. It is an ALLELE TRANSMISSION test.

If it is not they might be in LD - but could also be substructure - however if this is the case the pattern would defer between families.

Question 4

What are the assumptions for the TDT?

Answer 4

• Bi-alleic marker

- additive genetic model

Question 5

what is the FBAT?

Answer 5

Family based association test - supposed to be a generalization of the TDT.