Question

To estimate the number of cleavage sites in a particular piece of DNA with a known size, you can apply the formula \(N / 4^{n}\) where \(N\) is the number of base pairs in the target DNA and \(n\) is the number of bases in the recognition sequence of the restriction enzyme. If the recognition sequence for BamHI is GGATCC and the \(\lambda\) phage DNA contains approximately \(48_{1} 500 \mathrm{bp}_{1}\) how many cleavage sites would you expect?

Short answer

Question: Estimate the number of cleavage sites in the λ phage DNA using BamHI restriction enzyme, given its recognition sequence (GGATCC) and the number of base pairs in the λ phage DNA (481500). Answer: Approximately 118 cleavage sites.

Step-by-step solution

Identify the variables

To start solving the problem, we need to identify the variables given in the problem statement: - The number of base pairs in the target DNA (λ phage DNA): \(N = 48_{1} 500 \mathrm{bp}_{1}\) - The number of bases in the recognition sequence of the restriction enzyme: Length of BamHI recognition sequence (GGATCC) is 6 bases, so \(n = 6\).

Apply the formula

Now we will apply the given formula \(N / 4^{n}\) to estimate the number of cleavage sites: $$ \text{Number of cleavage sites} = \frac{N}{4^{n}} $$

Calculate the number of cleavage sites

Substitute the values of \(N\) and \(n\) into the formula to calculate the number of cleavage sites: $$ \text{Number of cleavage sites} = \frac{48_{1} 500}{4^{6}} $$ Evaluate the expression: $$ \text{Number of cleavage sites} = \frac{481500}{4096} \approx 117.68 $$

Interpret the result

Since the number of cleavage sites must be a whole number, we can round the result to the nearest integer. Therefore, you would expect approximately 118 cleavage sites in the λ phage DNA using BamHI restriction enzyme.

Key concepts

Cleavage Site Estimation

Understanding cleavage site estimation is crucial for biologists working with DNA. This concept involves predicting the number of sites within a DNA molecule where a specific restriction enzyme will cut.

To estimate the number of cleavage sites, we use the formula \(N / 4^{n}\), where \(N\) is the number of base pairs in the DNA and \(n\) is the length of the enzyme's recognition sequence. Since DNA is composed of four different nucleotides (adenine, thymine, cytosine, and guanine), the probability of a particular sequence occurring is based on these odds.

For example, if you were analyzing a DNA sample with 48,500 base pairs using an enzyme that recognizes a sequence 6 bases long, you'd calculate \(48,500 / 4^{6}\). The calculation results in about 117.68, rounded to 118 cleavage sites. This estimation is pivotal in genetic engineering and molecular biology for designing experiments and understanding DNA manipulation.

DNA Recognition Sequences

DNA recognition sequences are specific arrangements of nucleotides that are identified and bound by restriction enzymes. Each restriction enzyme has its unique recognition sequence, which is typically four to eight nucleotides long.

The sequence for BamHI is 'GGATCC'. It's a significant embrace of the specificity enzymes boast – no cutting unless this exact sequence is present. The precision of these sequences underpins many genetic techniques, allowing scientists to target specific regions of DNA for cleavage.

Understanding DNA recognition sequences is essential. It informs the selection of the appropriate restriction enzyme for experiments and is a fundamental aspect of genetic problem solving.

Genetic Problem Solving

Solving genetic problems often involves a blend of understanding key concepts and applying mathematical calculations. Approaching a genetic problem, like estimating cleavage sites for the BamHI restriction enzyme, first requires identifying the variables at play.

Then, you apply relevant formulas – in this case, the cleavage site estimation formula. As seen in calculating the number of BamHI cleavage sites in λ phage DNA, it's not just about executing the math but interpreting the results in a biologically relevant way.

A key to effective genetic problem solving lies in the ability to bridge these calculations with practical outcomes, such as predicting the number of DNA fragments that would result from the enzymatic action or planning cloning strategies.

Restriction Enzyme BamHI

BamHI is a type of bacterial enzyme used commonly in molecular biology for DNA manipulation. BamHI's claim to fame is its ability to recognize and cleave the 'GGATCC' sequence. Once it locates this sequence in DNA, it cleaves the bond between the guanine and adenine nucleotides, generating 'sticky ends'.

These sticky ends are crucial for techniques like DNA cloning, where you might insert a gene of interest into plasmid vectors. The precision and reliability of BamHI make it a powerful tool in genetic engineering, diagnostics, and research into gene function.