Jurassic Park and Genetics

[Trekker4747]

I've watched the Jurassic Park movies recently and I kind of got to wondering about some aspects of how the genetics is "supposed to work" in the movies compared to the real world.

For the sake of discussion we'll accept that it's conceivable and even plausible inGen was able to recover blood from prehistoric mosquitoes that were preserved in amber. Further allowing it was possible to take the recovered blood and use gene splicing to create dinosaurs. That's a LOT of hand waving we're giving them but it's all on some level "possible."

But here's some questions:

The first movie spends a lot of time going with the (now) popular theory that dinosaurs were more closely related to modern-day birds than reptiles. But when inGen created the Jurassic Park dinosaurs they spliced the recovered DNA with the DNA code of a frog in order to fill in the gaps in the degraded genetic code. Wouldn't this cause some problems? Splicing the DNA of a warm-blooded/bird-related animal with a cold-blooded reptilian animal? Wouldn't the result be anything BUT a dinosaur? Hell, wouldn't there be some pretty strong conflicts in the genetic code likely making a viable embryo unlikely? (Oddly enough in the background in that scene you can hear "Mr. DNA" tell the guests the zygote was implanted into a ostrich egg in order to mature.)

But, okay, the recovered dino-DNA needs to be spliced with something because over the millions of years its degraded and has holes. Why does it need to be spliced with anything? If a single drop of blood contains countless strands of DNA wouldn't it be possible to splice the DNA with itself? If we're to accept the geneticists were able to so easily fill in the gaps with the reptilian DNA then wouldn't be just as accepting that they could just scan multiple strands of DNA and piece together the gaps from other strands? Surely not all DNA strands are going degrade the exact same way.

And finally this is I think sort of the big one.

So the DNA between a dinosaur and a frog has been spliced together to create a "mostly-dinosaur-like" creature. (We'll assume that the reptilian DNA "worked better", took, and resulted in something that came out looking mostly like how we expect dinosaurs to look rather than the more bird-like looking things they likely actually were.) In the movie it's said that they bred all of the dinosaurs in Jurassic Park to be female in order to prevent breeding in the wild. I believe the book said they choose female because it was thought they'd be the tamer gender to go with in the movie (and probably also in the book) it's implied it's simply easier to deny an embryo the ability to become male since all embryos are inherently female anyway.

Of course in both the movie and the book "life finds a way" and the dinosaurs spontaneously change genders in the "wild" to produce offspring as some species of frog are known to do.

Here's the problem I see. The dinosaurs in Jurassic Park are hybrids! They're hybrids of dinosaurs and frogs. If I understand correctly hybrids are inherently sterile! (At least this is true when it comes to hybrid plants.) There should be no problems at all with breeding in Jurassic Park because all of their animals should naturally be born sterile. Sure, maybe, we can go with Malcolm's "life finds a way" theory with this and still breeding might happen, but almost as a rule hybrids can't breed. Nature pretty much doesn't accept hybrids because they're unnatural.

Hell, this is why bananas are fruits even though they don't contain seeds. Modern-day bananas have been selectively breed and spliced to create what we think of today as a banana. They don't have seeds because they're hybrids and are sterile. Same goes for most other seedless fruits. They're seedless because of genetic engineering by making hybrid plants.

So, thoughts?

[Silvercrest]

You're more correct than you realize. Frogs aren't reptiles. The DNA mismatch would be even worse.

The flip side, though: As to the hybrid thing, I don't think that's an ironclad rule... and this sort of hybridization is nothing like the real kind, when you should have even amounts of DNA from each donor. Here it's more like 99.9% dinosaur DNA and 0.1% "other". The creatures are technically hybrids, yes -- but effectively they really are dinosaurs. It stacks the deck more in favor of life "finding a way."

[Hound of UIster]

Silvercrest wrote:

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You're more correct than you realize. Frogs aren't reptiles. The DNA mismatch would be even worse.

They are just taking in account the concept that important coding sequences might have been conserved.

What is more unlikely was how the DNA information was able to be preserved. Without a buffer it would have denatured long ago.

Hell, this is why bananas are fruits even though they don't contain seeds. Modern-day bananas have been selectively breed and spliced to create what we think of today as a banana. They don't have seeds because they're hybrids and are sterile. Same goes for most other seedless fruits. They're seedless because of genetic engineering by making hybrid plants.

No these cases is more due to the fact that they were cultivated for their lack of seeds. Bananas are seedless for example because they are triploid and propagated by people who didn't like seeds . But you can make genetic hybrids all the time in the lab both animals and plants that incorporate genes from other organisms and are still capable of sexual reproduction.

[sojourner]

I never understood why Crichton used frog dna instead of bird dna to fill in the gaps.

[Trekker4747]

sojourner wrote:

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I never understood why Crichton used frog dna instead of bird dna to fill in the gaps.

Especially when he seemed to be on the "dinosaurs as birds" side of science.

In Jurassic Park, you'd think the inGen scientists/geneticists would've been smart enough to select a breed of frog NOT known to spontaneously change gender in a single-sex environment. Dr. Grant knew this pretty much just off the top of his head and he was hardly an expert in reptilian/amphibian genetics. How Dr. Wong (?) not know to select a breed of frog that couldn't do this?

[Tiberius]

Since we can easily splice fish DNA into vegetables to make them freeze resistant, I doubt the actual creatures you get the DNA from really matters all that much. many life forms have share the same genes. The gene for "Grow eye here" is very similar compared to humans and fruit flies.

[Gaith]

Next thing we know, you'll be suggesting that one can't recover from a broken back and a severe lack of cartilage with a few push-ups.

[sojourner]

^You don't. You have to be tied into a standing position by a piece of rope around you.

[Timelord_Victorious]

The frog DNA is the reason the velociraptors don't have feathers unlike the purebreds showing up in the next movie.

[The Borgified Corpse]

I have a more important scientific question. Jurassic Park is getting a 20th anniversary rerelease this year. How did I get so old?

Silvercrest wrote:

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The flip side, though: As to the hybrid thing, I don't think that's an ironclad rule... and this sort of hybridization is nothing like the real kind, when you should have even amounts of DNA from each donor. Here it's more like 99.9% dinosaur DNA and 0.1% "other".

Oh, like the bit in Superman III when Richard Pryor exposes Superman to Kryptonite contaminated with tar. It made him turn evil instead of killing him. NOW I get it!

[Robert Maxwell]

More important than what they replaced the missing DNA with was how they knew what was supposed to go where. DNA isn't exactly an instruction manual on how to build an organism--it just codes for various proteins, and it's the interactions and processes of those proteins that make an organism live or die. Essentially, they'd have to know what proteins are necessary to make the dinosaurs live, and where on their DNA chains the corresponding genes have to be located to work properly.

Once they determined what proteins are needed--and thus what genes--it doesn't really matter what species you get them from.

[Silvercrest]

The Borgified Corpse wrote:

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I have a more important scientific question. Jurassic Park is getting a 20th anniversary rerelease this year. How did I get so old?

Oh, like the bit in Superman III when Richard Pryor exposes Superman to Kryptonite contaminated with tar. It made him turn evil instead of killing him. NOW I get it!

Yes, that's what I was thinking of when I wrote it.

[gturner]

I'm pretty sure the reason Crichton went with frog DNA is to work in the sex-change angle for the plot, so life "could find a way" and thwart our hubris.

Jack Horner's plan to create dinosaurs involves chickens. Even though they're far from the most "dinosaur-like" bird, they're common, cheap, and caring for them is pretty trivial.

If none of you have seen his talk on creating a dinosaur, it's on Youtube. I went to the same talk when he came to my local university, sponsored by our geology department, since I hang out with dozens of geology students. Speaking of that, my suggestion for the best potential place to find intact dinosaur DNA is a blind valley (a bowl) down in Antarctica, where glacial action wouldn't have ground everything into the ocean and ice would've just sat there. By boring down to the bottom of such a valley with an ice-melting device, and then melting along horizontally, perhaps scientists could find relatively intact (but squashed) frozen ancient organisms.

Even as a sci-fi plot it would be better than a mosquito, combining Jurassic Park with The Thing.

[scotpens]

gturner wrote:

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Jack Horner's plan to create dinosaurs involves chickens. Even though they're far from the most "dinosaur-like" bird, they're common, cheap, and caring for them is pretty trivial.

Now just -- I say, just a doggone minute there, boy! Who are you callin' common and cheap?

[MLJames]

I thought the idea that they just used frog DNA was a plot simplification done for the film. It's been a good many years since I read the book, but IIRC Crichton had the InGen scientists using DNA from a number of different types of animals to patch the holes in the dino DNA, depending on which one was the most similar to the damaged gene sequence. I don't currently own a copy of the book, though, so if my memory's playing tricks on me, please let me know.