Analyse the following four pedigrees - HSC - SSCE Biology - Question 20 - 2020 - Paper 1
Question 20
Analyse the following four pedigrees.
KEY
☐ Unaffected female
☐ Unaffected male
● Affected female
● Affected male
1
2
3
4
Which row in the table corre... show full transcript
Worked Solution & Example Answer:Analyse the following four pedigrees - HSC - SSCE Biology - Question 20 - 2020 - Paper 1
Step 1
Identify the patterns in Pedigree 1
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In Pedigree 1, there is a clear pattern of affected males and females; since affected males can pass the trait to their daughters but not their sons, this suggests a sex-linked inheritance.
Step 2
Identify the patterns in Pedigree 2
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Pedigree 2 shows that the trait is passed on by affected females to both sons and daughters, indicating this could be autosomal dominant inheritance.
Step 3
Identify the patterns in Pedigree 3
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In Pedigree 3, both unaffected parents have affected offspring, suggesting that the trait is likely autosomal recessive.
Step 4
Identify the patterns in Pedigree 4
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Pedigree 4 shows affected males being fathered by unaffected parents, further supporting the idea of sex-linked recessive inheritance.
Step 5
Select the row that matches the pedigrees
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The correct identification of the pedigrees aligns with option C. Therefore, Pedigree 1 is sex-linked, Pedigree 2 is autosomal dominant, Pedigree 3 is autosomal recessive, and Pedigree 4 is sex-linked recessive.
