Zoo Blotting: Detecting Conserved DNA Sequences Across Species

A zoo blot helps to detect DNA sequences that
A. Are mutating at a fast rate.
B. Are conserved between species.
C. Are lost due to species extinction.
D. Are processed pseudogenes.

What Does a Zoo Blot Detect?

A zoo blot is a specialized form of Southern blotting that helps in identifying DNA sequences conserved across different species. The correct answer is:

✅ B. Are conserved between species.

How Does Zoo Blotting Work?

1. DNA Extraction from Multiple Species:

   • Genomic DNA is isolated from various organisms (e.g., humans, primates, rodents, birds, fish).

2. Restriction Enzyme Digestion:

   • The DNA is cut into fragments using restriction enzymes.

3. Agarose Gel Electrophoresis:

   • DNA fragments are separated based on size through electrophoresis.

4. Transfer to a Nitrocellulose or Nylon Membrane:

   • The DNA is blotted onto a membrane for further analysis.

5. Hybridization with a Labeled Probe:

   • A radioactive or fluorescent DNA probe specific to a gene of interest is applied.

6. Detection:

   • If a gene is evolutionarily conserved, the probe will hybridize to DNA from multiple species, appearing as a signal on an autoradiograph.

Why Is Zoo Blotting Important?

• Identifies evolutionarily conserved genes shared among species.
• Helps in comparative genomics and phylogenetics.
• Used to detect genes with important biological functions.

Why Are the Other Options Incorrect?

❌ A. Detects fast-mutating sequences – Zoo blotting identifies highly conserved, slowly evolving genes, not rapidly mutating ones.

❌ C. Detects extinct species’ DNA loss – Zoo blotting compares living species, not extinct ones.

❌ D. Detects processed pseudogenes – Pseudogenes often lack conservation; zoo blotting focuses on functional genes.

Conclusion:

Zoo blotting is a powerful comparative genomics tool, allowing scientists to identify conserved genes that play critical roles in evolution and biological functions across species.