Why Sequence the Pufferfish?

The Japanese pufferfish Takifugu rubripes (formerly designated Fugu rubripres) has the smallest known genome of any vertebrate species. As vertebrates, fish and humans share not only the defining characteristic of a backbone, but also many basic anatomical and physiological similarities. The compact Takifugu genome contains the same basic vertebrate blueprint as the human genome in a sequence seven times shorter. This difference is primarily due to the scarcity in Takifugu of the large repeat-filled tracts that litter the human genome. The relative compactness of the Takifugu genome simplifies the detection and analysis of both gene sequences and gene regulatory elements.

The initial analysis of the Takifugu sequence helps illuminate the human genome. By comparing the human and Takifugu sequences, common functional elements such as genes and regulatory sequences can be recognized as having been preserved in the two genomes over the course of the 450 million years since the species diverged from their common ancestor. By contrast, nonfunctional sequences are randomized over this long time period. More than 30,000 Takifugu genes have been identified in our analysis. The great majority of human genes have counterparts in Takifugu, and vice versa, with notable exceptions including genes of the immune system, metabolic regulation, and other physiological systems that differ in fish and mammals. Nearly 1,000 previously unrecognized human genes are predicted by comparing the two genomes. Remarkable stretches of sequence were found containing dozens of genes whose linkage is conserved between humans and Takifugu, shedding light on the large-scale evolutionary processes that shape genomes.

Genome Portal site: Fugu rubripres