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5. The HTT gene in humans is found on human chromosome 4 at position 16.3. It is unusual in that the gene has a repeating sequence of the triplet CAG which translates to the amino acid glutamine. The repeating sequences occur at the beginning of the gene and the number of these trinucleotide repeats varies, if it is between 7 and 35, there is no effect on the individual, but a greater number of repeats can lead to the Huntingtin protein being non-functional and to cause developmental problems in those who possess this variant of the gene, resulting in an inherited condition, known as Huntington disease. The severity of the disease is linked to the number of trinucleotide repeats.
c. The image shows the HT
1 d bzx8.(9z-9 onitk-yszqvvmm.tu1T protein in an individual with 30 repeats:
This protein has 30 CAG repeats and functions normally.
Suggest how the addition of 120 glutamine amino acid molecules to this HTT protein might cause the protein to become non-functional.