BIRTH defects such as Down’s syndrome may be due to a defect in a protein
that ensures that sperm and egg cells get the right number of chromosomes, say
Marion Shonn and her colleagues at the University of California in San
Francisco.
When cells divide, the duplicate sets of chromosomes are pulled apart by
spindle fibres. Checkpoint proteins make sure that the chromosomes are properly
attached to the spindle. Shonn’s team has found that a yeast checkpoint protein,
mad2, plays a critical role in the type of division that produces sperm and
eggs. If it is faulty, cells produce spores…
