THE publication of the pufferfish genome last week brings us closer to unlocking the secrets of our own DNA. The international team that did the work say they have been able to predict the existence of at least 900 as-yet undiscovered human genes.
Ever since the massive effort to uncover the human genome, researchers have been rushing to sequence the genomes of other creatures. The idea is that these will serve as Rosetta stones, unlocking the secrets of our own genome.
There are ongoing projects to sequence the genomes of the mouse and zebrafish as well as the pufferfish Fugu rubripes, with preliminary results being posted on the Internet as they emerge. But the pufferfish consortium, based in Singapore, Britain and the US, is the first to analyse and publish its sequence. The work will appear in Science.
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The team has stumbled on several oddities, including pufferfish genes that are up to four times as large as their counterparts in humans. 鈥淲e find that very puzzling,鈥� says team leader Samuel Aparicio of Cambridge University. The researchers also found that the fish have a huge variety of 鈥渏umping genes鈥�, bits of DNA that have the ability to copy themselves, giving rise to repetitive strings of DNA. Despite this diversity, such sequences make up just 15 per cent of the pufferfish鈥檚 DNA, compared with more than half of ours.
The pufferfish was chosen because it is one of our most ancient vertebrate relatives. Our two lineages diverged from a common ancestor about 450 million years ago. It also has a compact genome, with roughly the same number of genes as us, yet only an eighth as much DNA.
鈥淭he sequencing only took a few months,鈥� Aparicio says. The researchers anticipate it will take until April of next year to finalise the pufferfish sequence. By then, they expect to have uncovered evidence for a further 1000 human genes.
A similar analysis of the mouse genome is expected later this year. And other projects unravelling the genomes of rats, apes, frogs and chickens are in the pipeline.