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Examine the following pedigree, which shows the phenotype with respect to the ABO gene locus of each individual - VCE - SSCE Biology - Question 11 - 2012 - Paper 1
Question 11
Examine the following pedigree, which shows the phenotype with respect to the ABO gene locus of each individual. Individuals that would be homozygous at the ABO gen... show full transcript
Worked Solution & Example Answer:Examine the following pedigree, which shows the phenotype with respect to the ABO gene locus of each individual - VCE - SSCE Biology - Question 11 - 2012 - Paper 1
Step 1
Individuals that would be homozygous at the ABO gene locus include A. 13.
Answer
To determine if individual 13 is homozygous, we need to observe the parents' genotypes. Since individual 13 has phenotype AB, which arises from one A allele and one B allele, individual 13 cannot be homozygous.
Step 2
Step 3
Individuals that would be homozygous at the ABO gene locus include C. 116.
Answer
Similar to the previous analysis, we see that if individual 116 exhibits a phenotype that could only result from two copies of the same allele, this would require both parents to have contributed the same allele. If 116 is either AA or BB, then they are homozygous.
Step 4
Individuals that would be homozygous at the ABO gene locus include D. 112.
Answer
Finally, individual 112 could potentially show a phenotype that leads us to believe they are homozygous. Therefore, this would require further analysis of immediate parentage. In conclusion, D is the only option that satisfies the homozygosity condition based on the observed genotypes.