Question

Why does a high frequency of replication errors occur when DNA polymerases copy microsatellite regions of the genome?

a. DNA polymerases tend to stall in these regions.
b. DNA polymerases tend to slip as it moves along the template in these regions.
c. DNA polymerases tend to insert mismatched bases in these regions.
d. DNA polymerases tend to digest the template strand in these regions.
e. DNA polymerases tend to excise sections of the template strand in these regions

Answer 1

Replication errors frequently occur in microsatellite regions because DNA polymerases can slip, leading to mutations. DNA polymerases have proofreading and mismatch repair mechanisms, but they can still make mistakes in these repetitive sequences.

Step-by-step explanation:

A high frequency of replication errors occurs when DNA polymerases copy microsatellite regions of the genome because DNA polymerases tend to slip as they move along the template in these regions. This slippage can lead to the insertion or deletion of nucleotides, resulting in mutations or microsatellite instability. Although DNA polymerases have a proofreading capability to correct most mistakes during replication, the repetitive nature of microsatellites increases the chances that errors will escape correction.

While DNA polymerases are generally faithful in copying the genetic material due to their proofreading ability and other repair mechanisms such as mismatch repair, microsatellite regions present a unique challenge. These areas are prone to mistakes that can have serious consequences, like cancer, if the errors are not corrected and mutations become fixed in the genome.