You have isolated a genomic clone with an EcoRI fragment of 11 kb that encompasses the CRABS CLAW gene (see Problem 18). You digest the genomic clone with HindIII and note that the 11-kb EcoRI fragment is split into three fragments of 9 kb, 1.5 kb, and 0.5 kb.

Does this tell you anything about where the CRABS CLAW gene is located within the 11-kb genomic clone?

Verified step by step guidance

1. Step 1: Understand the problem setup. You have a genomic clone containing an 11-kb EcoRI fragment that includes the CRABS CLAW gene. When digested with HindIII, this fragment is split into three smaller fragments of 9 kb, 1.5 kb, and 0.5 kb. The goal is to determine if this digestion provides information about the location of the CRABS CLAW gene within the 11-kb fragment.
2. Step 2: Recognize that restriction enzymes like EcoRI and HindIII cut DNA at specific recognition sites. The fact that HindIII splits the 11-kb fragment into three pieces indicates that there are two HindIII recognition sites within the EcoRI fragment.
3. Step 3: Consider the sizes of the HindIII fragments (9 kb, 1.5 kb, and 0.5 kb). These sizes represent the distances between the HindIII recognition sites within the 11-kb EcoRI fragment. The CRABS CLAW gene must be located within one of these three fragments.
4. Step 4: To determine the location of the CRABS CLAW gene, additional experiments would be needed, such as hybridization with a probe specific to the CRABS CLAW gene or sequencing of the fragments. These techniques can identify which HindIII fragment contains the gene.
5. Step 5: Conclude that while the HindIII digestion provides a map of the EcoRI fragment, it does not directly reveal the exact location of the CRABS CLAW gene. However, it narrows down the possibilities to one of the three HindIII fragments (9 kb, 1.5 kb, or 0.5 kb).

Key Concepts

Restriction Enzymes

Restriction enzymes, like EcoRI and HindIII, are proteins that cut DNA at specific sequences. Understanding how these enzymes work is crucial for analyzing DNA fragments. In this scenario, EcoRI cuts the genomic clone into an 11-kb fragment, while HindIII further digests it into smaller pieces, providing insights into the structure and location of genes within the DNA.

Genomic Cloning

Genomic cloning involves isolating and amplifying specific DNA fragments from an organism's genome. The 11-kb EcoRI fragment containing the CRABS CLAW gene is a result of this process. Analyzing the sizes of the fragments produced by subsequent digestion helps determine the arrangement of genes and regulatory elements within the cloned DNA.

Gene Mapping

Gene mapping is the process of determining the location of genes on a chromosome. The fragmentation pattern observed after HindIII digestion suggests that the CRABS CLAW gene is likely located within the 11-kb EcoRI fragment, as the sizes of the resulting fragments can indicate the proximity of the gene to the restriction sites. This information is essential for understanding gene organization and function.