Lecture 20

Question 1

What are sex-linked traits

Answer 1

genes on sex chromosomes (x or y)

rather than autosome

Question 2

What are the inheritance patterns of colour blindness

Answer 2

if males are carriers - all daughters carriers/sons normal

if female carriers - half daughter carrier/half sons colourblind

Question 3

how many linked genes are there per chromosome

Answer 3

23 -pairs of chromosomes - 1000 linked genes per

-linked genes show bias towards parental genotype

Question 4

How does recombination happen in liked genes

Answer 4

‘crossing over’ during meiosis
- two chromatids of a tetrad (one from each pair) cross over at random points and swap genetic material. This is a simple cross where only one chiasma has formed

Question 5

What is the recombination frequency

Answer 5

the proportion of recombinant gametes

Question 6

What happens when the distance between two genes is smaller

Answer 6

it is less likely a chiasma will be formed between them (0-50%) compared to 50% of distant