Tetrahymena thermophila is a free-swimming unicellular protist. This freshwater organism inhabits streams, lakes, and ponds. Like other ciliates, Tetrahymena cells have a complex genome structure. Each cell contains a diploic micronucleus (mic) and a somatic macronucleus (mac).
The two nuclei function independently and have distinct functions and chromosomal arrangements. The mic is organized into 5 pairs of chromosomes and undergoes mitotic and meiotic division but is not transcribed. In contrast, during the formation of the mac, these chromosomes undergo site-specific fragmentation into approximately 200-300 chromosomes ranging in size from 21 kb to >3000 kb to which telomeric ends are added de novo. During this process, approximately 10% of the genome is removed. Mac chromosomes are amplified to a ploidy of approximately 45 copies except for the 21 kb ribosomal DNA minichromosome which is amplified to ~9000 copies. Transcription and translation occur in the macronucleus.
The Institute for Genomic Research (TIGR) has sequenced the macronuclear genome of Tetrahymena thermophila using a whole genome shotgun approach.
The T. thermophila whole genome sequence data as well as scaffold assemblies with annotation are available in GenBank and in RefSeq.
Last modified: Oct 17 2007