Professor Ruth Blake quoted in Newsweek on the potential of phosphate isotope measurements as a biosignature for possible life on Mars.

“On Earth, phosphate [isotopes] have a strong biological signature, distinct from the igneous basaltic and abiotic background, and Earth has proven a good analog for Mars based on past analyses of phosphate isotope ratios and petrographic analysis of Martian meteorites,” Ruth Blake, professor of Earth and planetary sciences at Yale University, who was also not involved, told Newsweek.

https://www.newsweek.com/mars-organic-compounds-found-carbon-life-nasa-study-1719554