Life as we know it on Earth is composed of at least six chemical elements: carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus. Scientists have long believed that life on other planets may arise differently, and now there's finally some evidence in the form of an arsenic-loving bacteria found in the arsenic-rich waters of Mono Lake in California. The bacteria are unique as they use arsenic in place of phosphorus, but it appears to be an evolutionary adaptation rather than a "second genesis" of life on Earth:
The researchers began to grow the bacteria in a laboratory on a diet of increasing levels of arsenic, finding to their surprise that the microbes eventually fully took up the element, even incorporating it into the phosphate groups that cling to the bacteria's DNA.
Notably, the research found that the bacteria thrived best in a phosphorus environment.
That probably means that the bacteria, while a striking first for science, are not a sign of a "second genesis" of life on Earth, adapted specifically to work best with arsenic in place of phosphorus.