All of the bases in DNA and RNA have now been found in meteorites
A 2-gram chunk from this rock — a piece of the meteorite that fell near Murchison, Australia, in 1969 — contains two crucial components of DNA and RNA now identified for the first time in an extraterrestrial source, researchers say.
Space rocks that fell to Earth within the last century contain the five bases that store information in DNA and RNA, scientists report April 26 in Nature Communications.
These “nucleobases” — adenine, guanine, cytosine, thymine and uracil — combine with sugars and phosphates to make up the genetic code of all life on Earth. Whether these basic ingredients for life first came from space or instead formed in a warm soup of earthly chemistry is still not known (SN: 9/24/20). But the discovery adds to evidence that suggests life’s precursors originally came from space, the researchers say.
Scientists have detected bits of adenine, guanine and other organic compounds in meteorites since the 1960s (SN: 8/10/11, SN: 12/4/20). Researchers have also seen hints of uracil, but cytosine and thymine remained elusive, until now.
