Science: Defining DNA/Retracting science/Womb cancer gene/Bomb or earthquake?/HIV lives

Telomerase, the enzyme that repairs the telomere - the "fuse" on the end of DNA - may not be the fountain of youth after all. Experiments in mice have shown that you can rebuild telomeres without the enzyme. "This might mean telomerase is simply a back-up enzyme," said Tom Lindahl of the Imperial Cancer Research Fund. Tough on the US companies that have invested millions in hope of an anti-ageing breakthrough.

"Occasional retraction of published data is a normal part of the scientific process." So notes the journal Science - where, you'll recall, a study about pesticides, later found to be faulty, was published. Science is now issuing notice not only of breakthroughs, but also their converse - retractions - in its publicity material. The latest are some chemistry papers from 1994 and 1995 on a new spectroscopic technique to identify the bonding arrangement of atoms in an enzyme. Hope your PhD doesn't rely on it.

Gene of the week is one that may be linked to cancer of the womb. A team at the University of Maryland School of Medicine in Baltimore and Tohoku University School of Medicine in Japan, reported in Nature Genetics that they found a mutation of the PTEN gene, on chromosome 10, in 55 per cent of the women they studied who had cancers of the endometrium (the lining of the uterus). Initial speculation is that PTEN may be a tumour suppressor gene - like its more famous cousin p53 - whose failure can allow cancer. Endometrial cancer is the sixth leading cause of cancer deaths among American women, with about 35,000 diagnoses annually.

Was it a bomb? Was it an earthquake? The latter, say American seismologists, who say that US intelligence sources are ignoring publicly available data which would show that there was a small "seismic event" about 130km off the coast of northern Russia. However, the Department of Defense said that the event, on August 16, had "explosive characteristics" - indicating that Russia might be carrying out underground nuclear testing. That would undermine the Clinton-backed Comprehensive Test Ban Treaty, which the Republican party in the US opposes, as do some DoD sources.

A live HIV vaccine test - where 50 volunteers agreed to be injected with a "weakened" virus - could still cause Aids, says Boston scientist Ruth Ruprecht. She told New Scientist: "Weakening the virus's ability to replicate is not a safe vaccine strategy."

The German molecular biologist who admitted faking data in research papers has been dismissed from her job. Marion Brach, a professor at the University of Lubeck, admitted in May to falsifying data. Colleague Friedhelm Herrmann, has also been charged but has denied wrongdoing.