Small but perfectly formed, Pelagibacter ubique is a lean machine stripped down to the bare essentials for life.Humans have around 30,000 genes that determine everything from our eye colour to our sex but Pelagibacter has just 1,354, US biologists report in the journal Science. What is more, Pelagibacter has none of the genetic clutter that most genomes have accumulated over time. There are no duplicate gene copies, no viral genes, and no junk DNA. 'Chicken soup'The spareness of its genome is related to its frugal lifestyle. The shorter the length of DNA that needs to be copied each generation, the...