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Friday, November 7, 2008

Mommy, I want a saber-toothed kitten!

In 1990, the late Michael Crichton published his most influential book. Sure, a lot of us loved 'State of Fear', but let's be honest - that's not his most popular book. If you haven't been under a rock through the '90s, you've probably heard of it - Jurassic Park. Of course, the series' portrayal of dinosaurs may have been a bit off (we now know the velociraptors had feathers, for example), but the idea was pure brilliance. Resurrecting animals from blood stored in preserved mosquitos - genius, and eventually, maybe even possible. This, the week of his death, scientists have published a few breakthroughs that just might make his vision a reality.

Read the rest of this post!

The past week or so has been a good one for paleogenetics and those crazy Russians and Japanese hoping to recreate the Pleistocene in Siberia. The past may be able to come alive again after all. Hopefully, at least, researchers hoping to revive extinct species won't have to turn to the russian mafia for samples anymore.

The first big step is that Japanese scientists have successfully cloned a mouse. But they didn't just clone any mouse - they cloned a mouse that had been frozen solid for 16 years.

The problem with cloning frozen specimens, in the past, has been an issue of damage. Cloning is generally done by fusing the donor cell with a de-nucleated egg cell, leaving you with a egg that contains your desired DNA that can be implanted in a surrogate mom. But cells from frozen tissue are horrifically damaged - their membranes simply can't handle the fusing process. So how did Japanese researchers from RIKEN solve the issue? They essentially said 'screw the broken membranes' and developed a method to inject the entire damaged cell into an egg.

After playing around trying to clone frozen mice with minimal success, the researchers found that some organs worked better than others. Blood was good, but brain matter was even better. Finally, the group managed to clone embryos from frozen brain tissue with a success rate of 39% - about that of fresh tissue.

Did I mention the head researcher's eventual goal? He is working to create technology to clone mammoths, sabertooth tigers, giant deers, and steppe lions from frozen genetic material. "There are many technical challenges involved in resurrecting a mammoth, but we have shown that the nuclear transfer method can be used to create healthy clones, even when the animal’s cells have been damaged by permafrost-like conditions," lead author Teruhiko Wakayama said. Just to let you know - if I get to see a saber tooth tiger or a mammoth in my lifetime, I'll be able to die unbelievably happy.

The second good news for paleogeneticists or anyone hoping to bring back the dinosaurs is that researchers have sequenced the first complete mitochondrial genomes from cave bear specimens that are tens of thousands of years old and NOT preserved in permafrost. A paper (published online this week) presents "the first mitochondrial genome" from the extinct cave bear, Ursus spelaeus (actually, another paper last July did the same thing, but I'll let them squabble about that).

What's particularly big is that they did so for specimens that weren't preserved in permafrost (although the ice is damaging to the cell itself, it does preserve DNA better than if its not frozen). This opens the field of complete mitochondrial sequencing to a wide range of extinct species - maybe even those trapped in amber (so maybe that's a stretch...). Even if the amber is out, being able to get intact DNA from an animal that hasn't been frozen is a big step in cloning animals that didn't live during the Ice Age.

Every discovery is getting us a little closer to making Crichton's fantasy a reality. OK, so we might see a living mammoth or velociraptor next month. But we are getting closer - and come on, don't pretend you wouldn't spend a ridiculous amount of money on tickets to a real Jurassic or Pleistocene Park. And if they do have a real Jurassic Park, I think they should name it in Crichton's honor.

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