Jurassic Park made it all look so easy: in a remote laboratory, a team of scientists extracts DNA from the guts of hundred-million-year-old mosquitoes petrified in amber (these pesky bugs, of course, feasted on dinosaur blood before they died). The dinosaur DNA is combined with frog DNA (an odd choice, considering that frogs are amphibians rather than reptiles), and then, by some mysterious process that's presumably too difficult for the average moviegoer to follow, the result is a living, breathing Velociraptor straight out of the Cretaceous period.
In real life, though, cloning a dinosaur would be a much, much more difficult undertaking. That hasn't prevented an eccentric Australian billionaire, Clive Palmer, from recently announcing his plans to clone dinosaurs for a real-life, down-under Jurassic Park. (One presumes that Palmer made his announcement in the same spirit that Donald Trump tested the waters for a presidential bid--as a way of attracting attention and headlines.) Is Palmer one shrimp short of a full barbie, or has he somehow mastered the scientific challenge of dinosaur cloning? Let's take a closer look at what's involved.
Dinosaur Cloning Step #1: Obtain a Dinosaur Genome
DNA--the molecule that encodes all of an organism's genetic information--has a notoriously complex, and easily breakable, structure consisting of millions of "base pairs" strung in a specific sequence. The fact is that it's extremely difficult to extract a full strand of DNA from a 10,000-year-old Woolly Mammoth frozen in permafrost; imagine what the odds are for a dinosaur, even an extremely well-fossilized one, that has been encased in sediment for over 65 million years. Jurassic Park had the right idea, DNA-extraction-wise; the trouble is that dinosaur DNA would degrade even in the relatively isolated confines of a mosquito's fossilized tummy.
The best we can reasonably hope for--and even that's a stretch--is to recover scattered fragments of a particular dinosaur's DNA, accounting for perhaps one or two percent of its entire genome. Then, the hand-waving argument goes, we might be able to supplement these DNA fragments with strands obtained from the modern descendants of dinosaurs, the birds. But which species of bird? How much of its DNA? And, without knowing what a complete Diplodocus genome looks like, how would we know where to insert the dinosaur DNA remnants?
Dinosaur Cloning Step 2: Find a Suitable Host
Ready for more disappointment? An intact dinosaur genome, even if one were ever miraculously to be found, wouldn't be sufficient, by itself, to clone a dinosaur. You can't just inject the DNA into, say, an unfertilized chicken egg, then sit back and wait for your Apatosaurus to hatch. The fact is that most vertebrates need to gestate in extremely specific conditions, and, at least for a short period of time, in a living body (even a fertilized chicken egg spends a day or two in the mother hen's oviduct before it's laid).
So what would be the ideal "foster mom" for a cloned dinosaur? Clearly, if we're talking about a genus on the larger end of the spectrum, we'll need a correspondingly hefty bird, if only because dinosaur eggs were much bigger than chicken eggs. (That's another reason you couldn't hatch a baby Apatosaurus out of a chicken egg; it's just not capacious enough.) An ostrich might fit the bill, but we're so far out on a speculative limb now that we might as well just consider cloning a giant, extinct bird like Gastornis or Argentavis!
Dinosaur Cloning Step 3: Cross Your Fingers (or Claws)
Let's put the odds of successfully cloning a dinosaur into perspective. Consider the common practice of artificial gestation involving human beings--i.e., in vitro fertilization. No cloning or manipulation of genetic material is involved, just introducing a sperm to an egg, cultivating the resulting zygote in a test-tube for a couple of days, and implanting the embryo-in-waiting into the mother's uterus. Even this technique fails more often than it succeeds; most times, the zygote simply doesn't "take," and any genetic abnormalities will cause a termination of the pregnancy weeks, or months, after the implantation.
Compared to IVF, cloning a dinosaur is almost infinitely more complicated. We simply don't have access to the proper environment in which a dinosaur embryo can gestate, or the means to tease out the information encoded in dinosaur DNA in the proper sequence and with the proper timing. Even if we got as far as implanting a full dinosaur genome into an ostrich egg, the embryo would, in the vast majority of cases, simply fail to develop. Long story short: pending some major advancements in science, there's no need to book a trip to Australia's Jurassic Park!