[5] For example, the MAT locus found in this species has provided a foundation for the evolution of mating systems.

They have a bigger, non-germline macronucleus and a small, germline micronucleus in each cell at the same time and these two carry out different functions with distinct cytological and biological properties.

This unique versatility has allowed scientists to use Tetrahymena to identify several key factors regarding gene expression and genome integrity.

[13] When T. thermophila is exposed to UV light it results in a greater than 100-fold increase in the expression of the gene for the DNA repair enzyme Rad51.

[14] Treatment with the DNA alkylating agent methyl methanesulfonate also resulted in substantially elevated Rad 51 protein levels.

These findings suggest that ciliates such as T. thermophila utilize a Rad51-dependent recombinational pathway to repair damaged DNA.

Meiosis in T. thermophila appears to employ a Mus81-dependent pathway that does not use a synaptonemal complex and is considered secondary in most other model eukaryotes.

The Sgs1 helicase appears to promote the non-crossover outcome of meiotic recombinational repair of DNA,[17] a pathway that generates little genetic variation.

[13] In 1982, the group 1 intron was discovered located in the rRNA transcript of this species[23]: 82  by Thomas Cech and his coworks.

[24]: 205  This was considered the first ribozyme, a piece of RNA that can catalyze a reaction, in this case self-splice from a primary transcript without the help of proteins.