Tiny timekeepers

日期:2018-01-06 04:06:44 作者:柯攵 阅读:

SOME bacteria have biological clocks similar to those of flies and people. An international team of researchers has identified three clock genes in a group of bacteria that rely on the Sun for energy. Photosynthetic microbes called cyanobacteria are the most primitive organisms known to have a daily cycle of gene activity. Even without light, they continue to switch on genes for photosynthesis during the day. Now Takao Kondo of Nagoya University in Japan and colleagues have isolated the genes responsible and dubbed them kaiA, B and C (kai is Japanese for cycle). Although the gene sequences are very different from those of genes that regulate daily rhythms in animals, Kondo believes the way the clock works is similar. One gene, kaiA, turns on the other two, which then turn themselves off again (Science, vol 281,