How is genomic instability defined?

Genomic instability is defined as an increased tendency for genomic alterations during cell division. This increased tendency can lead to various forms of damage to the DNA, such as mutations, deletions, duplications, and chromosomal rearrangements. Genomic instability is a significant underlying factor in many diseases, particularly cancer, as it accelerates the rate at which cells acquire mutations that can contribute to tumorigenesis. In a healthy cellular environment, mechanisms exist to stabilize the genome and repair genetic damage; however, when these mechanisms are compromised, genomic instability can arise, leading to a cascade of genetic alterations.

The other definitions provided do not accurately describe genomic instability. For instance, stabilization of the genome during cell division would indicate a normal and healthy genomic state, while a reduction in genetic mutations and a consistent repair mechanism for DNA depict effective genomic maintenance—a clear contrast to the concept of genomic instability, which inherently involves the failure of these protective processes.