Biology Question - Genetics

Mario95

This question is from a HL Biology mock I did recently.
I am just wondering if someone could do it. It would be great if you could explain how you interpreted this question.

To me, it seems like there is not enough information to answer this question properly (ie. its too vague and ambiguous). Do you share my opinion?

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b) Haemochromatosis is a genetic disorder in humans caused by a change in one base in a single gene which controls iron levels in the body. The change in the gene occurs so that the (codon) triplet reads ATA instead of ACA.

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vi) The gene discussed above follows a normal monohybrid inheritance pattern. Use the family tree below to predict the genotype of individuals 1, 2 and 3.

The family tree (copy URL): s9.postimg.org/vytk97yy7/image.gif
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aleatorio

My first notion would be that 1 and 2 are heterozygous because they had an effected offspring, and then 3 would be homozygous dominant because no offspring are effected

IrishKnight

As some of the offspring of 1 and 2 the disorder, 1 and 2 must be carriers for the disorder. This also tells us that the disorder is a recessive disorder. The people that have the disorder must be hh, therefore 1 and 2 are both likely to be Hh.

The male who has offspring with 3 can only give h to his offspring. As either suffer from the disorder, it is likely 3 is HH.

While I'm not sure if it is on the LC, geneticists generally assume that someone from outside of the family wouldn't be a carrier anyway...

To me, it seems like there is not enough information to answer this question properly (ie. its too vague and ambiguous). Do you share my opinion?

The question asks you to predict the genotype based on the information provided. It is impossible to be 100% correct all the time in genotyping using trees. Can only be certain by using DNA sequencing