It could be argued that the ‘ultimate’ soft tissue is DNA. The sequence of nucleotide bases in DNA encodes the genetic information in an organism and this information is used to synthesize proteins and other molecules essential for the proper functioning and development of the organism. Although DNA is stable, it is fragile; certain chemicals, such as strong acids or alkalis, can break the sugar-phosphate backbone of DNA or modify the bases, resulting in DNA damage. DNA can be physically damaged by mechanical forces such as shearing forces that break the strands or by physical disruption during cell division or other cellular processes. Enzymes known as nucleases can degrade DNA by cleaving its phosphodiester bonds, and these enzymes are crucial for various cellular processes including DNA repair and DNA degradation during programmed cell death (apoptosis).
Over time, DNA naturally degrades and this begins immediately post-mortem. The presence of water can accelerate this process. Researchers and scientists handling DNA in laboratories take special precautions to preserve its integrity. For example, DNA samples are often stored at low temperatures and protective measures are taken to avoid exposure to UV light and contaminants. Additionally, special techniques, such as DNA extraction and purification protocols, are used to minimize damage during experimentation.
Based on experimentation some researchers have calculate DNA half-life of less than 1000 years:
“By analysing mitochondrial DNA (mtDNA) from 158 radiocarbon-dated bones of the extinct New Zealand moa, we confirm empirically a long-hypothesized exponential decay relationship. The average DNA half-life within this geographically constrained fossil assemblage was estimated to be 521 years for a 242 bp mtDNA sequence, corresponding to a per nucleotide fragmentation rate (k) of 5.50 x 10-6 per year” (Allentoft et al, Proc. R. Soc. B (2012) 279, 4724–4733).
But DNA has been reported in mammoths and more recently in dinosaurs…So, the question is, how does any DNA survive into deep time (> 1M years)? Could it be that the concept of deep time itself has a half life and at we are approaching the end of its time as a useful concept?
There are now more than 120 papers in peer-reviewed journal articles reporting soft tissues in dinosaur and other deep-time organic remains. These scientific papers describe biological material, including tissue and DNA, remaining inside fossils. A full list, which is being continually updated, is provided here: *List of Biomaterial Fossil Paper
Example papers for this topic: (58) Dino DNA & proteins actin, tubulin, PHEX, histone 2012
(109) Cretaceous DNA for mitochondrial cytochrome b 2012
(121) Caudipteryx chromatin/DNA 2021
*This list of biomaterial papers can provide useful information for research and posting on topics within the Dinosaur Project Community. Thanks to researchgate.net for making this list freely available.