Why is avoiding long homopolymers important in DNA data storage?

• A. They have no impact on sequencing.
• B. They improve sequencing accuracy.
• C. They increase sequencing errors and misreads, reducing data reliability.
• D. They reduce synthesis cost.

Answer: (C)

Long homopolymers create problems for sequencing because the signal used to call bases becomes ambiguous when a single nucleotide repeats many times. Polymerases can slip on long runs, leading to insertions or deletions, and base-calling algorithms may misestimate the exact length of the run. In DNA data storage, where data is encoded as sequences and later decoded from those reads, these errors can distort the stored information and reduce data reliability. So avoiding long homopolymers helps keep reads faithful to the original data, improving accuracy during retrieval. The other statements aren’t correct because long homopolymers do impact sequencing, they don’t improve accuracy, and while synthesis can be affected by sequence patterns, the primary issue at stake here is sequencing error and data integrity.