SINGAPORE - Scientists have completed a rough draft of the genome of the Japanese puffer fish, a step the researchers say will accelerate discovery of human genes.

The puffer fish, or Fugu rubripes, is an ideal candidate for genome research because its genetic code is so short. Although it contains many of the same genes that the human genome has, it's only about one eighth the length.

Because it doesn't have as much so-called junk DNA, repeating sequences that aren't involved in making proteins, the researchers say it'll be easier to isolate genes from the puffer fish genome.

That could settle the question of how many genes humans have. The current estimate is between 30,000 and 40,000 genes. Fugu has between 35,000 and 40,000.

The Fugu puffer fish is a delicacy in Japan, but a naturally occurring neurotoxin can make the fish deadly if prepared improperly.

The fish can puff themselves up into a spiky ball three times their normal size if they are threatened.

Even though the most recent common ancestor of puffer fish and humans lived over 450 million years ago, it is believed they share many genetic control sequences.

These parts of the genome control how genes are expressed and are believed to be crucial to all vertebrate life.

The group responsible for the work, based in Singapore, the United Kingdom and the United States, will publish an analysis of the genome next year and the sequence data will be publicly available.