Sea squirts aid fertility research

Sea squirts have a similar fertilisation process to humans

The humble sea squirt is helping pioneering research into human infertility.

The tiny slug-like creatures, which are found in their millions along the coast of North East England, have embryos very similar to humans.

A team of scientists from Newcastle University believes they may offer vital clues to the whole fertilisation process without the need to experiment on human eggs and embryos.

It is a remarkable facet of biology that the sea squirt has a very similar biology at fertilisation to humans

Dr Keith Jones, University of Newcastle

Although the sea squirt is a very basic animal, it is in fact thought by some to share a common ancestor with humans as it has a backbone.

For this reason, its earliest stages of life are almost identical to those of a human.

Scientists are concentrating on the point at which sea squirt sperm fertilise sea squirt eggs.

They are trying to isolate the protein in the sea squirt's sperm which triggers fertilisation. This is known as the activating factor.

Transfer findings

Sea squirt facts

Sea squirts are also known as squirters and dead men's fingers

The Japanese consume about 20 tonnes of them each year

The French eat them raw with lemon juice. In Sette, a fishing town west of Marseille, they are sold in paper bags like chips

If successful, they believe they can transfer their findings to human sperm and thus aid research into infertility and its causes.

The theory is that the protein in sperm which triggers chemical changes in the egg, leading to embryo development, is defective or missing from the sperm of some infertile men.

Researcher Dr Keith Jones told the BBC: "It is a remarkable facet of biology that the sea squirt has a very similar biology at fertilisation to humans."

Dr Jones said using human eggs and sperm for research was fraught with legal and ethical difficulties.

There were also problems with having to screen human material for diseases such as HIV and hepatitis.

"We think we have nicely circumvented all those problems by going after the sea squirt activating factor first.

"We are hoping that we can identify the factor within a couple of years, and hopefully we can come up with the human equivalent within a matter of months."

The researchers regularly collect sea squirts from Blyth Harbour in Northumberland, where they are regarded as a pest because they foul up ropes and chains by attaching themselves in huge numbers.