- "It was in the last days of genetic recovery, and at this point, nothing was certain. Was the DNA there?"
- —John Hammond(src)
It is a matter of debate whether DNA can be preserved in amber for millions of years.
Preservation characteristics amber
Amber is a unique preservational mode. Amber dehydrates its inclusions, which stabilizes the DNA molecules. Bada et al. (1999) created a model that predicted that DNA can be preserved in amber for 100 million years.
DNA recovered from amber
Whether DNA can survive 65 million years in amber is a matter of scientific debate. It was long believed that in ideal conditions (like permafrost) DNA could only survive for a million years. This dogma wasn't challenged by experimental evidence until the research of Allentoft in 2012,
In 1992 DeSalle (who later wrote The Science of Jurassic Park) and his team reported that they had extracted and sequenced DNA from a termite (Mastotermes electrodominicus) entombed in 25-30 million year old amber.
The first discovery of Mesozoic DNA was claimed by Cano and his team (see video). They claimed that they had extracted and sequenced two DNA fragments from a 120-135-million-year-old weevil (Lebanorhinus succinus). One fragment (315 nucleotides long) coded for part of ribosome RNA. The other fragment (226 nucleotides) coded for a piece non-functional RNA.
Many scientists have criticised these discoveries. Many scientists were unable to extract DNA from comparable samples. Some have claimed the DNA was the result of contamination. Scientists Gutierrez and Marın showed in 1998 that the latter Cretaceous Weevil sequence showed more resemblance with DNA from the fungus Pichia guilliermondii (known to them as Candida guilliermondii) than insects.
The scene featuring a close-up of the mosquito clearly shows fuzzy antennae, meaning the particular insect is male. This was likely for a cinematic effect, as only female mosquitoes suck blood.
- Bada J.L., Wang X.S., Hamilton H. (1999). Preservation of key biomolecules in the fossil record: Current knowledge and future challenges, Philos Trans R Soc Lond B, Volume 354, pages 77–87.
- Allentoft M.E., Collins M., Harker D., Haile J., Oskam C.L., Hale M.L., Campos P.F., Samaniego J.A., Gilbert M.T.P., Willerslev E., Zhang G., Scofield R.P., Holdaway R.N., Bunce1 M. (2012) The half-life of DNA in bone: measuring decay kinetics in 158 dated fossils, Proceedings of the Royal Society Biological Sciences, Volume 279, page 4724-4733.
- DeSalle R., Gatesy J., Wheeler W., Grimaldi D., (1992) DNA Sequences from a Fossil Termite in Oligo-Miocene Amber and Their Phylogenetic Implications, Science, Volume 257, page 1933-1936. Link
- Cano R.J., Poinar H.N., Pieniazek N.J., Acra A., Poinar G.O. Jr. (1993) Amplification and sequencing of DNA from a 120-135-million-year-old weevil. Nature, Volume 363(6429), page 536-8.
- DNA sequence L08072 on GenBank.
- Never included on GenBank. Sequence is shown here: Cano ITS sequence
- Hebsgaard M.B., Phillips M.J., Willerslev E. (2005) Geologically ancient DNA: fact or artefact?, TRENDS in Microbiology, Volume 13(5), page 212-220. Link
- Gutierrez G., Marın A., (1998) The Most Ancient DNA Recovered from an Amber-Preserved Specimen May Not Be as Ancient as It Seems. Mol. Biol. Evol., Volume 15(7), page 926–929. Link