2,5-Dimethylfuran from ≈2.7 × 10 ⁹ -year-old Rupemba—Belingwe stromatolite, Rhodesia: Potential evidence for remnants of carbohydrates

Abstract

2,5-Dimethylfuran, 2-methylfuran, and C9-C20 n-alkanes have been isolated from the kerogen of a Rupemba stromatolite. These furans could be the oldest known stable remnants of biological carbohydrates if it is possible to prove that their progenitors are as old as the rock. Experiments showed that it is improbable that these compounds are analytical artifacts or laboratory contaminations. Postdepositional contaminations caused by fluids flowing through the rocks seem doubtful because of minimal permeability, which is supported by petrographic observations. Contamination by diffusion also appears to be unlikely. Because the rock had a mild temperature history, these molecuies could have survived since Archean time. Because of all the evidence, the furans and alkanes are quite likely biochemical fossils.

Biogenicity of Morphologically Diverse Carbonaceous Microstructures from the ca. 3400 Ma Strelley Pool Formation, in the Pilbara Craton, Western Australia

“…Moreover, furan molecules detected in stromatolite-hosted ca. 2700 Ma kerogen (Sklarew and Nagy 1979) suggest the preservation of Archean carbohydrates, which are the main primary constituents of EPS. Very fine strands that interconnect to form a laminated web-like network similar to the SPF threads were observed in the ca.…”

Origin of DNA Repair in the RNA World

“…Protocellular organisms may have come into existence 2.5 to 3.5 billion years ago [1,2]. Woese [3] proposed that the genomes of the early protocellular forms of life were individual strands of RNA rather than DNA, and that these RNA strands were present as separate genome segments, rather than being linked together end-to-end as is generally the case for genes in DNA.…”