marine pest can offer scientists a way of studying human infertility
while avoiding many controversial embryo experiments, British researchers
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.
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.
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.
role in infertility research is the result of work by scientists
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
Of Cell Science.
of Rasberry Tunicates (Didemnum)
Sea Squirts (Rhopalaea crassa)
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.
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.
of the protein appears to be a major cause of infertility and sea
squirt fertilisation is governed by a very similar protein to the