Key to coral warming stress

But one of the advantages of the new technique, as much of the media pointed out, is the ability to discriminate between afflicted males and, indeed, carrier and normal females. PGH can identify the 50 per cent of male embryos that will be unaffected, said Allison Lashwood, a consultant nurse at Guy's and St Thomas' Hospital in London. " We can tell the difference between the affected and the unaffected males and that, for some couples, will make a difference between whether they get an embryo transfer or not, " Lashwood said. " By using this technology we are hopefully increasing the number of embryos, " she said. Pam Renwick, the geneticist at Guy's Hospital who has pioneered the test's development, said that the technique can be applied to any genetic disease where the mutation has been located on a region of a particular chromosome. " It's a universal test for all families and it has the added advantage that we can now select for unaffected males, which increases the number of embryos for transfer into the womb, " Renwick said. The PGH test can also distinguish between female embryos that are healthy carriers of a defective gene from those that are completely free, non-carriers. This raises the ethical issue of whether to offer couples the opportunity to discard female embryos that are healthy carriers in favour of healthy non-carriers. Braude said: " If you are looking at the eugenic implications of saying that we are trying to eliminate a disease from a family, that's a completely different story from what we are trying to do, " he said. " This is nothing to do with screening. This is to do with families at significant risk who can choose this technique over pre-natal diagnosis and termination of pregnancy. The easy way is you get pregnant, test the pregnancy and abort if it is no good. Some people have done that repeatedly and don't want to do it again, or they have religious objections to termination, " he said. Coral reefs and the diversity of ocean life they attract and shelter are major tourist attractions in many areas around the world from the Caribbean to the South Pacific. Now it appears that human activities, including tourism, are putting their very existence at risk. A first warning sign was the bleaching of corals, observed in many locations since the late 1980s. Apparently, …