IT MAY look like a bloated pincushion when threatened, but the pufferfish
turns out to have one of the leanest genomes of all the vertebrates. The
鈥渕inimalist鈥� genome of Fugu rubripes could help unlock the secrets of
the much grander human genome, researchers from Singapore told the conference,
by helping to identify which genes are vital to a vertebrate.
鈥淭he pufferfish genome is one-eighth the size of the human genome, but has
the same repertoire of genes,鈥� says Byrappa Venkatesh of the Institute of
Molecular and Cell Biology in Singapore. The genomes of pufferfish and humans
are very different, having diverged from a common ancestor 400 million years
ago. Nevertheless, 鈥渨e can identify conserved regions that are likely to be
important and which perform the same function now as then,鈥� he says.
To test this, Venkatesh and his collaborators at Bristol and Berkeley,
California, inserted a pair of adjacent genes from the fish into rats. The genes
produce the hormones oxytocin and vasopressin, which regulate salt and water
balance and smooth muscle contraction in the fish. In rats, the same two genes
are expressed separately in different types of neurons in the hypothalamus.
Advertisement
When Venkatesh put the fish genes into rats, the genes were expressed in
exactly the same way as their rat counterparts. So knowing what a gene does in
the fish should help to work out what a corresponding newly discovered human
gene does in people.