Question

1. the following diagram shows the result of a test that was done using dna samples from three bears of different species. each dna sample was cut into fragments using a specific restriction enzyme and placed into the wells of a gel as indicated below. the dna fragments were then separated using gel electrophoresis. the arrow represents the direction of movement of the dna fragments. what is responsible for the movement of dna in this process? (0.25 pt) which two species of bear have a closer evolutionary relationship? (0.25 pt) how does the gel electrophoresis tell you that? (0.5 pt)

Explanation:

• Movement of DNA: DNA is negatively charged due to its phosphate groups. In gel electrophoresis, an electric field is applied. The negative charge of DNA causes it to move towards the positive electrode (opposite charges attract).
• Closest evolutionary relationship: Bear 1 and Bear 3. In gel electrophoresis, similar DNA fragment patterns (in terms of number, size, and position) suggest a closer genetic similarity. Genetic similarity is an indicator of a closer evolutionary relationship. Bear 1 and Bear 3 have more DNA fragments that are in similar positions (indicating similar - sized fragments) compared to Bear 1 - Bear 2 or Bear 2 - Bear 3.

Answer:

• The movement of DNA is due to its negative charge (from phosphate groups) moving towards the positive electrode in the electric field.
• Bear 1 and Bear 3 have a closer evolutionary relationship.
• Gel electrophoresis shows this because Bear 1 and Bear 3 have more DNA fragments of similar size (as indicated by their similar positions on the gel) compared to other pairs.