"Few researchers have given credence to claims that samples of dinosaur DNA have survived to the present day, but no one knew just how long it would take for genetic material to fall apart. Now, a study of fossils found in New Zealand is laying the matter to rest — and putting an end to hopes of cloning a Tyrannosaurus rex." (source 1)
Allentoft et al. have discovered that DNA in bones can only last for 6.8 million years (source 2). Which "is nowhere near the age of a dinosaur bone — which would be at least 65 million years old" (source 1).
Many Jurassic Park fans became really disappointed when they heard this. But that isn't needed! Let me explain why this research doesn't prove we can't recreate dinosiaurs.
These people say that there can't be any DNA in dinosaur bones... DUH! Scientists and Michael Crichton have assumed for a long time that there is no DNA left in dinosaur bones. Scientists DeSalle and Lindley claimed in their book How To Build A Dinosaur that dino bones only contain minerals; no tissue, no proteins, no DNA. The take home message of Allentoft et al. is that DNA is too unstable to last long in bones.
BUT Jack Horner has proved there ARE proteins and soft tissue in dinosaur bones. The article Proteins in fossils lists all dino protein sequences that have been discovered yet. From the protein code the DNA code can be deduced. Let me show you:
Lets translate that into DNA code...:
- "Bingo! Dino-DNA!"
The complete set of T. rex DNA consists of 1.77 – 2.32 billion letters (Source 3). NOT 3 billion as Mr. DNA claims. So, we still have a long way to go before we can clone a T. rex. Moreover, only 4% of T. rex' DNA coded for proteins. I think that because that is the case in modern birds.
10% of T. rex' genome consisted of a few short functionless sequences repeated over and over again (in humans that is 40%!). These sequences are found in all animals, so they are known. (Source 3)
However, what did the rest of the T. rex DNA looked like? This 86% of the genome contained very important elements. To name a few: promotors, enhancers, histone binding sites, introns. Therefore, another source of DNA is needed.
Michael Crichton also knew that bones would never yield a 100% complete DNA set. Therefore he came up with the idea of Dino DNA in amber. It is good to remember that Allentoft et al. measured the DNA degradetion in bones not amber. We know that DNA can last much longer in amber because Poinar isolated DNA from a 40 million year old insect stuck in amber.
An insect of pieces of flesh containing T. rex DNA has never been discovered, but... have scientists really looked at it? It is very possible that somewhere a prehistoric bug is waiting.
We could also compare the DNA of birds and deduce what their ancestor's (the dinosaurs) genome must have looked like. The genomes of the following reptiles and birds are fully sequenced. Comparing the genomes of these creature (see Comparative genomics) could give valuable insights.
- Carolina anole (arboreal lizard) (2011)
- Gallus gallus (chicken) (2004)
- Meleagris gallopavo (Turkey) (2011)
- Taeniopygia guttata (Zebra Finch) (2010)
Even if we can discover enough dino DNA, the story isn't over.
Remember, the whole reason we search for ancient T. rex DNA is that we don't understand how DNA creates an animal. Therefore, we hope the DNA still does. However, one day we will fully understand how DNA creates an animal. At that time we don't need ancient T. rex DNA anymore. We can just design it ex nihilo with a computer.
Lee M. Silver, Professor of molecular biology and public policy at Princeton University, wrote much about this in his book Challenging Nature: The Clash of Science and Spirituality at the New Frontiers of Life. He argues that with genetic modification man would (re)make a world wide Garden of Eden. Diseases would be destroyed, aging stopped, predators turned into kind vegetarians and ... mythological and extinct creatures created.
Much sections about the book were about the novel and movies of Jurassic Park, because these stories argued man could recreate dinosaurs. While most scientists had initially rejected the posibility of this recreation, Silver argues that it will most likely happen once:
- "...evolutionary developmental geneticists believe that comparisons of DNA in birds and reptiles -on either side of the evolutionary line leading to dinosaurs- could provide some, although not complete, insight into the extinct genome of dinosaurs. Genetic, developmental, and evolutionary understanding and data could be combined with molecular understanding to allow rational design of a dinosaur on a computer. Starting with a virtual chicken genome, virtual genetic changes could be implemented to increase overall adult size, eliminate feathers and restore scales, turn wings back into elongated front and back legs, and mold the virtual animal into a reasonable facsimile of a particular dinosaur, such as a giant long-necked apatosaurus, a triceratops, or even a Tyrannosaurus rex. The designed electronic genome would be converted into organic DNA with nano-DNA writing machines that automatically link up thousands of smaller DNA fragments into whole chromosomes. The genome would then be inserted into a chicken egg devoid of its own DNA -in an advanced version of the process that created Dolly- and presto, dinosaur facsimiles." (Source 4)
So wether we will use ancient DNA or design it ourselves on a computer, it makes no difference. In the future there will be dinosaurs.
If you want to know more about the science of recreating dinosaurs, see Recreating dinosaurs and all associated pages.
- Source 1: Nature News, 10 October 2012, DNA has a 521-year half-life Genetic material can't be recovered from dinosaurs — but it lasts longer than thought.
- Source 2: Allentoft, M. E. et al. Proceedings of the Royal Society B, link (2012).
- Source 3: Organ et al., Origin of avian genome size and structure in non-avian dinosaurs, Nature, Vol 446, 8 March 2007.
- Source 4: Lee M. Silver, Challenging Nature: The Clash of Science and Spirituality at the New Frontiers of Life, page 312-313.