Skip to main content
Pearson+ LogoPearson+ Logo
Ch. 7 - DNA Structure and Replication
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
Chapter 7, Problem 30

Using an illustration style and labeling, draw the electrophoresis gel containing dideoxy sequencing fragments for the DNA template strand 3'-AGACGATAGCAT-5'.

Verified step by step guidance
1
Understand the dideoxy (Sanger) sequencing method: This method uses a DNA template strand, DNA polymerase, primers, deoxynucleotides (dNTPs), and dideoxynucleotides (ddNTPs). The ddNTPs terminate DNA synthesis at specific bases, creating fragments of varying lengths.
Identify the DNA template strand: The given template strand is 3'-AGACGATAGCAT-5'. The complementary strand synthesized during sequencing will be 5'-TCTGCTATCGTA-3'.
Determine the fragments generated: For each ddNTP (ddA, ddT, ddC, ddG), DNA synthesis will terminate at the corresponding complementary base in the synthesized strand. For example, ddA will terminate at positions where 'T' is added, ddT will terminate at positions where 'A' is added, and so on.
Label the fragments: Arrange the fragments by size, with the shortest fragment (closest to the primer) at the bottom of the gel and the longest fragment at the top. Each fragment corresponds to a specific nucleotide position in the sequence.
Draw the electrophoresis gel: Create a diagram with four lanes labeled 'A', 'T', 'C', and 'G' for the ddNTPs. Place the fragments in the appropriate lanes based on their termination points, ensuring the smallest fragments are at the bottom and the largest at the top. Label the bands with their corresponding nucleotide positions.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Dideoxy Sequencing

Dideoxy sequencing, also known as Sanger sequencing, is a method for determining the nucleotide sequence of DNA. It involves the incorporation of dideoxynucleotides (ddNTPs) during DNA synthesis, which terminate the elongation of the DNA strand. This results in fragments of varying lengths that can be separated by electrophoresis, allowing for the identification of the sequence based on the size of the fragments.
Recommended video:
Guided course
08:41
Sequencing Difficulties

Electrophoresis

Electrophoresis is a laboratory technique used to separate charged molecules, such as DNA fragments, based on their size and charge. In the context of DNA sequencing, an electric field is applied to a gel matrix, causing the negatively charged DNA fragments to migrate towards the positive electrode. Smaller fragments move faster through the gel, allowing for the separation and visualization of different DNA sequences.
Recommended video:

DNA Template Strand

The DNA template strand is the strand of DNA that serves as a guide for synthesizing a complementary strand during processes like replication and sequencing. In the context of dideoxy sequencing, the template strand is read in the 3' to 5' direction, and the complementary fragments generated during sequencing will be in the 5' to 3' direction. Understanding the orientation of the template strand is crucial for accurately interpreting the resulting sequence.
Recommended video:
Guided course
03:03
Double Strand Breaks
Related Practice
Textbook Question

In a dideoxy DNA sequencing experiment, four separate reactions are carried out to provide the replicated material for DNA sequencing gels. Reaction products are usually run in gel lanes labeled A, T, C, and G.

How does PCR play a role in dideoxy DNA sequencing?

547
views
Textbook Question

In a dideoxy DNA sequencing experiment, four separate reactions are carried out to provide the replicated material for DNA sequencing gels. Reaction products are usually run in gel lanes labeled A, T, C, and G.

Why is incorporation of a dideoxynucleotide during DNA sequencing identified as a 'replication-terminating' event?

542
views
Textbook Question

The following dideoxy DNA sequencing gel is produced in a laboratory.

What is the double-stranded DNA sequence of this molecule? Label the polarity of each strand.

785
views
Textbook Question

A PCR reaction begins with one double-stranded segment of DNA. How many double-stranded copies of DNA are present after the completion of 10 amplification cycles? After 20 cycles? After 30 cycles?

562
views
Textbook Question

DNA replication in early Drosophila embryos occurs about every 5 minutes. The Drosophila genome contains approximately 1.8×10⁸ base pairs. Eukaryotic DNA polymerases synthesize DNA at a rate of approximately 40 nucleotides per second. Approximately how many origins of replication are required for this rate of replication?

739
views
Textbook Question

What would be the effects on DNA replication if mutation of DNA pol III caused it to lose each of the following activities?

5' to 3' polymerase activity

674
views