A piece of DNA has been sequenced by Ion Torrent™ sequencing. The result corresponding to a six-nucleotide segment of this DNA is presented in the graph below, in which pH change is recorded after the addition of each of the four nucleotide triphosphates in cycles. What is the sequence of this segment? All sequences are written from 5′ to 3′.
A) TACGTA
B) CGTACG
C) CCGTAA
D) CGGTTA
E) ATTGGC

Question

A piece of DNA has been sequenced by Ion Torrent™ sequencing. The result corresponding to a six-nucleotide segment of this DNA is presented in the graph below, in which pH change is recorded after the addition of each of the four nucleotide triphosphates in cycles. What is the sequence of this segment? All sequences are written from 5′ to 3′. 
A) TACGTA 
B) CGTACG 
C) CCGTAA 
D) CGGTTA 
E) ATTGGC

Quizplus · Accepted Answer

When each nucleotide is incorporated into DNA in the well that contains this sequence, the release of an H⁺ ion changes the pH, which is registered by a semiconductor chip. If the next position in the sequence has the same nucleotide, the nucleotide is incorporated twice, and twice as many protons are released, as is the case for G and T nucleotides in the example shown.

A Piece of DNA Has Been Sequenced by Ion Torrent™