Ch. 15 - Recombinant DNA Technology and Its Applications

Sanders - Genetic Analysis: An Integrated Approach 3rd Edition

Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook

Sanders 3rd Edition

Ch. 15 - Recombinant DNA Technology and Its Applications

Problem 15a

Chapter 15, Problem 15a

The bacteriophage lambda genome can exist in either a linear form or a circular form.
How many fragments will be formed by restriction enzyme digestion with XhoI alone, with XbaI alone, and with both XhoI and XbaI in the linear and circular forms of the lambda genome?

Verified step by step guidance

Step 1: Understand the lambda genome structure. The bacteriophage lambda genome can exist in two forms: linear and circular. In the linear form, the genome has free ends, while in the circular form, the ends are joined to form a loop. This structural difference affects how restriction enzymes cut the DNA.

Step 2: Learn about the restriction enzymes XhoI and XbaI. Restriction enzymes recognize specific DNA sequences and cut at those sites. For example, XhoI recognizes the sequence 5'-CTCGAG-3', and XbaI recognizes the sequence 5'-TCTAGA-3'. The number of fragments produced depends on the number of recognition sites in the genome.

Step 3: Determine the number of recognition sites for XhoI and XbaI in the lambda genome. This information is typically provided in the genome map or sequence data. Count the number of sites for each enzyme in both the linear and circular forms of the genome.

Step 4: Analyze the cutting pattern for each enzyme. In the linear form, each recognition site results in a cut that produces two fragments. In the circular form, the genome is a loop, so the number of fragments produced is equal to the number of cuts made by the enzyme.

Step 5: Combine the effects of both enzymes. When both XhoI and XbaI are used together, the total number of fragments is determined by the combined number of cuts made by both enzymes. Consider how overlapping recognition sites (if any) might affect the fragment count in both linear and circular forms.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

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

Bacteriophage Lambda Genome Structure

The bacteriophage lambda genome can exist in two forms: linear and circular. The linear form is typically found during the infection process, while the circular form can occur after the genome is integrated into the host's DNA. Understanding these forms is crucial for predicting how the genome will behave during restriction enzyme digestion.

Restriction Enzymes

Restriction enzymes, such as XhoI and XbaI, are proteins that cut DNA at specific sequences. XhoI recognizes the sequence CTCGAG, while XbaI recognizes the sequence TCTAGA. The number of fragments produced by digestion depends on the number of recognition sites present in the DNA, which varies between the linear and circular forms of the genome.

DNA Fragmentation and Analysis

When a DNA molecule is cut by restriction enzymes, it is fragmented into smaller pieces. The number of fragments generated can be calculated based on the number of cutting sites. In the case of the lambda genome, analyzing the resulting fragments from different enzyme combinations helps in understanding the genome's structure and the effects of the enzymes used.

Recommended video:

Guided course

02:48

Chi Square Analysis

Related Practice

Textbook Question

The bacteriophage ϕX174 has a single-stranded DNA genome of 5386 bases. During DNA replication, double-stranded forms of the genome are generated. In an effort to create a restriction map of ϕX174, you digest the z-stranded form of the genome with several restriction enzymes and obtain the following results. Draw a map of the ϕX174 genome.

645

views

Textbook Question

Three independently assorting STR markers (A, B, and C) are used to assess the paternity of a colt recently born to a quarter horse mare. Blood samples are drawn from the mare, her colt, and three possible male sires (S₁, S₂, and S₃). DNA at each marker locus is amplified by PCR, and a DNA electrophoresis gel is run for each marker. Amplified DNA bands are visualized in each gel by ethidium bromide staining. Gel results are shown below for each marker. Evaluate the data and determine if any of the potential sires can be excluded. Explain the basis of exclusion, if any, in each case.

635

views

Textbook Question

It is often desirable to insert cDNAs into a cloning vector in such a way that all the cDNA clones will have the same orientation with respect to the sequences of the plasmid. This is referred to as directional cloning. Outline how you would directionally clone a cDNA library in the plasmid vector pUC18.

724

views

Textbook Question

The bacteriophage lambda genome can exist in either a linear form or a circular form.

Diagram the resulting fragments as they would appear on an agarose gel after electrophoresis.

460

views

Textbook Question

A major advance in the 1980s was the development of technology to synthesize short oligonucleotides. This work both facilitated DNA sequencing and led to the advent of the development of PCR. Recently, rapid advances have occurred in the technology to chemically synthesize DNA, and sequences up to 10 kb are now readily produced. As this process becomes more economical, how will it affect the gene-cloning approaches outlined in this chapter? In other words, what types of techniques does this new technology have potential to supplant, and what techniques will not be affected by it?

729

views

Textbook Question

The restriction enzymes XhoI and SalI cut their specific sequences as shown below:

Can the sticky ends created by XhoI and SalI sites be ligated? If yes, can the resulting sequences be cleaved by either XhoI or SalI?

1563

views

The bacteriophage lambda genome can exist in either a linear form or a circular form. How many fragments will be formed by restriction enzyme digestion with XhoI alone, with XbaI alone, and with both XhoI and XbaI in the linear and circular forms of the lambda genome?

Verified video answer for a similar problem:

Key Concepts

Bacteriophage Lambda Genome Structure

Restriction Enzymes

DNA Fragmentation and Analysis

The bacteriophage lambda genome can exist in either a linear form or a circular form.
How many fragments will be formed by restriction enzyme digestion with XhoI alone, with XbaI alone, and with both XhoI and XbaI in the linear and circular forms of the lambda genome?