5.7 Tracing your family history

• Biologie
• Middelbare school
• havo, vwo
• Leerjaar 3

When a gene is located on the X-chromosome, we call this a ...

Can a man be a carrier for a sex-linked-gene?

Why do men have a higher chance of expressing a sex-linked-gene in their phenotype?

PEDIGREES

LET'S PRACTISE 

Could this disease be ...

a. autosomal dominant? 

b. autosomal recessive? 

c. X-linked dominant? 

d. X-linked recessive? 

Yes / No ? Explain your answer. 

Autosomes

Autosomes

'Normal' genes

AA - Aa - aa

Sex chromosomes

Sex-linked genes

XHXH - XHXh - XhXh 

XHY - XhY

LET'S PRACTISE 

Could this disease be ...

a. autosomal dominant? No

b. autosomal recessive? Yes

c. X-linked dominant? No

d. X-linked recessive? Yes

Yes / No ? Explain your answer. 

LET'S CHECK THE HOMEWORK

Download the answers from SOM &

Discuss the answers with a classmate. 

LET'S PRACTISE!

Download the exercises linked on SOM. 

Answer the exercises to practise how to calculate probabilities & apply your knowledge on mutations.