'Life' gene missing on volcanoes
A gene thought previously to be present in all life on earth is missing in microbes living in boiling acid near the summits of volcanoes.
The protein, thought to be one of the fundamental building-blocks of life, is not present in certain volcanic single cell organisms.
St Andrews university scientists studied archaea, which are similar to bacteria but have a separate origin.
They found the expected gene missing and another in its place.
The findings have been published in American journal Proceedings of the National Academy of the Sciences (PNAS).
The missing protein, named SSB, performs an essential role binding DNA and protecting it from damage.
Professor Malcolm White of the School of Biology at the University of St Andrews said: "All cells, whether they are microbial or human, have some things in common.
"These are the fundamental components or building blocks which were present in the first cells and have been passed on over 3.5 billion years.
"However, we have discovered that a gene normally thought to be absolutely essential and conserved throughout every form of life, is in fact lost in one group of volcanic bugs, and replaced by a completely novel gene we have christened ThermoDBP."