Mapping the Genome

Question 1

What happens when genes are linked?

Answer 1

• Alleles on the same chromosome will be the more common combination
• Alleles from each can only be combined through recombination
• The closer the genes are on a chromosome the fewer recombinant offspring

Question 2

How do you calculate the map distance between two genes?

Answer 2

no. recombinants/total progeny x 100

Question 3

What happens to genes >50cM apart?

Answer 3

• They behave as if unlinked

- Can still be mapped on the same chromosome by chromosome walking

Question 4

What does it mean if map distances don’t add up?

Answer 4

• A double cross over event

- Causes us to underestimate the map distance between the furthest genes

Question 5

What do we have to do when calculating recombinants in Sordaria?

Answer 5

Divide by two because some have been counted as recombinant which actually aren’t