Given the epic failure of the VelociRapture this weekend and my subsequent desire to watch Jurassic Park, I thought that this would probably be a good time to visit that age-old question: can you really make a dinosaur from mosquitoes caught in amber plus some random frog DNA?
While that question seems pretty forthright, it’s actually very complex scientifically. Let’s take it step by step.
Is amber good at storing DNA and protein?
The answer seems to be yes. The book Evolution of Insects by David A. Grimaldi and Michael S. Engle has a section that discusses using polymerase chain reaction (PCR) to amplify DNA found in different insects fossilized in amber. However, the problem was consistently that all samples were contaminated or degraded. Interestingly, the authors state that amino acids seem hardier and stick around longer. It has been suggested that DNA stored in amber is only good for 100,000 years. Not quite long enough to reach back to the Cretaceous period.
Have mosquitos been found with blood inside them?
No, not according to the San Diego Natural History Museum. In addition, according to the SDNHM, no insects in amber have been found that are from the Cretaceous Period.
How long does it take DNA to degrade?
The answer is not long. I know that we’ve all seen specials on the History Channel about PCR being done on mummies to verify familial relationships. However, if we’re talking about rebuilding a genome, the entirety of an organism’s hereditary information, we’re going to be out of luck very quickly. DNases and RNases go to work very quickly, nomming up the building blocks that make up the genome. If I leave DNA out on my bench overnight, the next morning it is often degraded and non-usable for most sensitive purposes, let alone the possible degradation that would occur after 65 million years.
Another snag with the DNA quality would be the digestive enzymes of the mosquito. Those enzymes go to work very quickly and are very hostile to macromolecules, meaning that DNA wouldn’t hang around all that long in an intact state.
Well, no problem, they used frog DNA to supplement?
That’s actually a big problem. First off, we know now that birds are actually more likely to be evolutionary descendants of dinosaurs. Second, birds are very, very, very far off evolutionary descendants. What this means is that there likely isn’t enough genetic relatedness to substitute even bird DNA for dinosaur DNA. And what you do substitute? The DNA for wings? Tyrannosaurus rex didn’t have wings. Scientists can’t go mucking around adding random sequences from different species. In recent years, it has become increasingly obvious that even what scientists had once called “junk DNA” actually has important sequences that regulate other DNA, so even that isn’t safe to replace.
Amber to DNA to Dinosaur
How do you get from the recreated genome to the dinosaur?
This is the most difficult problem of all. Scientists can use machines to synthesize strands of DNA called Oligonucleotides (Oligo – few or little, nucleotide ““ the bases of DNA = short DNA strands) but how do you get longer strands of DNA, how do you condense those strands into chromosomes? How do you replicate DNA, generate proteins? There is a lot of cellular machinery necessary to get from DNA to organism. DNA must be built into a cell, a process which is called which is called transformation. An egg is specifically what is needed and there aren’t any dinosaur eggs around. There really isn’t anything close to use as a substitute.
Scientists did recently generate an entirely synthetic genome and place it into a bacterium that had had its genome removed. It replicated, though not entirely without problems. Even this giant scientific step forward does not solve the problem of the lack of dinosaur eggs.
Unfortunately, it is not possible to make dinosaurs the way Michael Crichton imagined in Jurassic Park. I know I will never stop loving the movie!
Most work done with insects in amber is done regarding insect evolution. There is a really awesome NPR story entitled “Insects in Amber Provide Clues to India’s Past“ regarding this subject. I suggest you take a listen!