This article is from The Times

Marine pests offer help for human life

Monday 20th November 2000

Sea Squirt Colony

A slimy marine pest can offer scientists a way of studying human infertility while avoiding many controversial embryo experiments, British researchers have discovered.

The eggs sperm and embryos of the sea squirt, an invertebrate so common in British waters that it is regarded as a pest, are so similar to those of people that they can be substituted for human samples in many laboratory experiments.

As a result, infertility researchers will now be able to bypass many of the ethical problems of working with human embryos.

Sea squirts also offer a possible answer to a shortage of donated eggs, and a way for scientists to bypass the tight regulation that surrounds human embryo research.

The sea squirt, also known as dead man's fingers, is a small slug-like creature that was previously best known for eating its own brain: once it has found an appropriate rock to set up home on it has no further use for its brain, and digests it. It is edible - the French eat it raw with lemon juice - and particularly popular in Japan, where tonnes are consummed annually.

Its new role in infertility research is the result of work by scientists at Newcastle and Durham universities, who have shown that aspects of the creature's reproductive system are similar to that of humans, making it a peculiarly good match for research purposes. Their results are published in the Journal Of Cell Science.

Colony of Rasberry Tunicates (Didemnum)

Pastel Sea Squirts (Rhopalaea crassa)

Sea squirts do not move about or have sexual intercourse, but they nevertheless use eggs and sperm to reproduce. The animals inject eggs or sperm into the sea, where the sperm seek out, penetrate and fertilise the eggs, as they do in the human womb.

The North East team, who collect sea squirts for their own use from Blyth Harbour in Northumberland, are now using them to isolate a key sperm protein that is thought to "activate" eggs on fertilisation.

Failure of the protein appears to be a major cause of infertility and sea squirt fertilisation is governed by a very similar protein to the human one.

Author: Mark Henderson