Question

380 bp 270 bp 220 bp 200 bp A B C D E F

          380 bp
270 bp
220 bp
200 bp
A B C D E F

Added by Dana R.

Biology for AP Courses

Julianne Zedalis, John Eggebrecht

Instant Answer

Solved by Expert Madhur L

06/21/2023

Step 1

Huntington's disease (HD) is caused by the expansion of a CAG trinucleotide repeat in the HTT gene. The number of repeats determines the likelihood of developing the disease and can influence the age of onset. Typically, individuals with 40 or more repeats will Show more…

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The trinucleotide repeat region of the Huntington disease locus (HD) in six individuals is amplified by PCR and analyzed by gel electrophoresis as shown in the following figure; the numbers to the right indicate the sizes of the PCR products in bp. Each person whose DNA was analyzed has one affected parent. A) Which individuals are most likely to be affected by Huntington disease, and in which of these people is the onset of the disease likely to be earliest? B) Which individuals are least likely to be affected by the disease?