Replication slippage occurs when the DNA polymerase dissociates from the DNA strand, causing the duplication or loss of genes. Replication slippage can also lead to changes in the number of repeats present in satellite DNA - this can be used in paternity and forensic DNA testing.
Different numbers of repeats on satellite can result in varying severity of genetic disorders - Huntington’s disease becomes more severe with the expansion of the CAG repeat region.