Science: Update

SPERM CELLS are screened for genetic fitness before they mature, but the process breaks down with age, say American scientists. Tests on mice by the University of Texas could explain why the children of older fathers are more likely to have birth defects. Live sperm tend to have fewer genetic mutations than other cells. Researchers found cells at the early stage of development are more likely to carry a mutation. By maturity, when the sperm are ready to be ejaculated, mutations had halved. But in old mice mutations were up to 10 times greater than in younger mice, the team told New Scientist magazine.

FIELD TRIALS of genetically modified crops in Germany face opposition from regional governments. Rainder Steenblock, the environment minister of Schleswig-Holstein, wants the law changed so Germany's 16 states have a say in whether trials can go ahead inside their boundaries.

THE SUCCESS of land plants is due to an accidental duplication of a singe gene early on, say researchers in the US and Germany. The gene is responsible for a protein called actin, which plays a key role in forming the framework of cells. Scientists at the University of Iowa found that while algae and marine plants have one copy of the actin gene, land plants have at least two.

A TRIBE of Apaches signed a deal with American geneticists stating it will receive a share of profits from research using genes taken from the tribe's blood samples. The work aims to investigate the genes that confer resistance and susceptibility to disease, reports New Scientist. In return, the tribe will retain anonymity, and the genetic data will not be compared to other tribes.

NUCLEAR WASTE buried underground can migrate to the surface through plant roots, according to scientists at the Oak Ridge National Laboratory in Tennessee.