Skip to main content
Premium Trial:

Request an Annual Quote

Researchers Sequence Smallest Genome Yet; Bacterial Endosymbiont Has Only 182 Genes

NEW YORK (GenomeWeb News) – An international research team has sequenced the genome of Carsonella ruddii, a symbiotic bacteria that has the fewest genes of any organism sequenced to date.  
The genome of C. ruddii, which lives inside certain cells in a small insect called a psyllid, has only 159,662 base pairs and 182 protein-coding genes, according to a paper published in today’s Science.
The bacteria’s genome is only one-third the size of the previously reported smallest cellular genome, the archaeal parasite Nanoarchaeum equitans, which was sequenced in 2003.
Co-author Nancy Moran, a professor at the University of Arizona, said in a statement that the small size of the organism’s genome was “very surprising.”
Moran said that even though endosymbionts generally need fewer genes to survive as compared to free-living bacteria, the researchers had not expected so few in C. ruddii. “It's believed that more genes are required for a cell to work," she said.
One explanation for the "streamlined" genome, the authors write in the Science paper, is that some C. ruddii genes may have been transferred into the host genome, enabling the insect to make some of the metabolites the bacteria needed. 

The Scan

Myotonic Dystrophy Repeat Detected in Family Genome Sequencing Analysis

While sequencing individuals from a multi-generation family, researchers identified a myotonic dystrophy type 2-related short tandem repeat in the European Journal of Human Genetics.

TB Resistance Insights Gleaned From Genome Sequence, Antimicrobial Response Assays

Researchers in PLOS Biology explore M. tuberculosis resistance with a combination of sequencing and assays looking at the minimum inhibitory concentrations of 13 drugs.

Mendelian Disease Genes Prioritized Using Tissue-Specific Expression Clues

Mendelian gene candidates could be flagged for further functional analyses based on tissue-specific transcriptome and proteome profiles, a new Journal of Human Genetics paper says.

Single-Cell Sequencing Points to Embryo Mosaicism

Mosaicism may affect preimplantation genetic tests for aneuploidy, a single-cell sequencing-based analysis of almost three dozen embryos in PLOS Genetics finds.