Which phenomenon describes the increasing number of repeats across generations?

The phenomenon that describes the increasing number of repeats across generations is known as triple repeat extension. This occurs when specific sequences of nucleotides, often consisting of the same three bases repeated several times, accumulate during the replication process. This phenomenon is particularly significant in the context of certain genetic disorders, such as Huntington's disease and some forms of muscular dystrophy, where the increase in these repeated sequences can lead to an earlier onset and more severe symptoms in successive generations.

Triple repeat extension highlights the mechanisms behind how certain genetic traits can expand over time, leading to changes in phenotype as the number of repeats increases. This expansion can occur due to slippage during DNA replication, where the DNA polymerase mistakenly adds additional copies of the repeat unit. Hence, the presence of such repeat expansions illustrates a unique genetic inheritance pattern, distinct from more traditional Mendelian inheritance where traits are passed down without such fluctuations in genetic sequence length.