[2] They serve to encode large numbers of genes at a time.
TAGs represent a large proportion of genes in a genome, including between 14% and 17% of the human, mouse, and rat genomes.
[2] An example are tandem clusters of rRNA encoding genes.
In order to provide the necessary ribosomes, multiple RNA polymerases must consecutively transcribe multiple rRNA genes.
[3] In some species, such as Arabidopsis thaliana and Oryza sativa, most TAGs are the result of unequal chromosomal crossover during genetic recombination.