Differences and similarities between various tandem repeat sequences: minisatellites and microsatellites

Area of Science:

• Genomics
• Molecular Biology
• Genetics

Background:

• Tandemly repetitive DNA sequences are widespread in eukaryotic genomes.
• These sequences exhibit species-specific occurrence and location.
• Repetitive sequences can generate variants with altered repeat numbers, a phenomenon known as instability.

Purpose of the Study:

• To review the factors influencing repetitive DNA sequence instability.
• To demonstrate that no universal rule governs repetitive sequence instability.
• To highlight the role of local and general biological activities in determining instability.

Main Methods:

• Review of existing literature on repetitive DNA sequences.
• Analysis of proposed mechanisms for sequence instability (e.g., DNA polymerase slippage, unequal recombination).
• Examination of factors affecting instability, including repeat number, sequence content, chromosomal location, DNA repair, and cell cycle stage.

Main Results:

• Repetitive DNA sequence instability is influenced by numerous parameters, including sequence characteristics, cellular environment, and reproductive context.
• Mutations in repetitive sequences are implicated in human diseases like cancer and dominant inheritance disorders.
• Two primary mechanisms, DNA polymerase slippage and unequal recombination, are proposed to explain instability.

Conclusions:

• The instability of repetitive DNA sequences is a complex phenomenon.
• Each repetitive sequence possesses a unique instability profile determined by its specific biological context.
• Understanding these factors is crucial for comprehending genome stability and disease pathogenesis.