On the Cloning of Mammoths
October 11, 2008
I first came across the idea of Pleistocene Rewilding in an issue of Scientific American. It grabbed my fascination. The basic idea–the subtleties, nuances and beauty of which I completely gloss in this stunted summary–is that because North American megafauna from the Pleistocene ice age were erased from this continent by human activity, humans have caused a vast and deep ecosystemic impact.
The loss of these animals is revealed by the holes they left behind. Relict species such as the pronghorn demonstrate this. Pronghorn can run 55 m.p.h., despite having no extant predator that comes anywhere close in speed. They must have co-evolved with very fast predator. Interestingly, fossil evidence reveals that there were North American cheetahs that lived alongside pronghorn during the Pleistocene.
So to finish my stunted summary, there are advocates for establishing a vast animal park in the western U.S., re-wilded with surrogate species for the missing Pleistocene megafauna. Bactrian camels, African cheetahs, and so on. Such a massive endeavor could help preserve endangered species from around the world, while restoring some potentially ecologically vital behavior of missing megafauna. (Most notably, wherever elephants exist, the landscape is substantially affected by their behavioral presence. What is the long term impact from the disappearance of the mastodon and Columbian mammoth?)
If this is the first time you have come across the idea of Pleistocene Rewilding, please research it more, as I have given it unfortunately short shrift. There are many counterarguments that I don’t consider in my summary, though I am well versed in the impracticaities, risks, and rationales for not pursuing such a massive undertaking. But that’s not why I started writing this. I started writing because of the problem with elephants.
As I understand it, neither African nor Asian elephants would make suitable surrogate species for Columbian mammoth. The western North American climate is quite different–harsher winters most notably–from that of the extant elephants. It would seem that there’s not a modern surrogate to be had. However, one line of thinking proposes that this is not a limitation to restoring elephants to North America. We might be able to restore mammoths through cloning. I decided to research a bit.
Here’s the idea summarized nicely by Page Paleontological Center:
The Idea — French explorer Bernard Buigues and Larry Agenbroad, Northern Arizona University hope that Jarkov Wooly Mammoth sitting inside a 23-ton block of ice will contain flesh sample with some perfectly preserved DNA. That and some proven cloning technology could resurrect a long-gone species.
What Buigues and his team would do is something similar to the process that created the famous sheep Dolly: extracting the nucleus of one adult mammoth cell and inserting it into an empty egg cell. The embryo would then be implanted in the uterus of an Asian elephant, the mammoth’s closest living relative, a surrogate mother that would gestate it as its own but without transferring to the baby any of the elephant’s genes.
For the past 20,380 years, this 10-foot-tall mammal weighing more than 2 tons has remained buried under 4½ feet of permafrost in the steppes of northern Russia. When the frozen mammoth was pulled out last year, expedition leaders suggested the possible presence of soft tissue would make it possible to clone the extinct animal. There is a lot we can do with even bad DNA.
We believe we have a 100 percent chance of finding parts of the mammoth, which died at 47 years old, still intact,” Buigues said. Its head and trunk were closest to the surface, exposed to climate changes, and they have deteriorated, but not the rest of the body. Its woolly skin is in good condition and we think its internal organs and possibly even its stomach contents are as well.
There should be little problem in getting DNA if the animal is well preserved.
So that sounds really hopeful. But the same page goes on to state:
The Reality – Finding intact parts, however, does not necessarily mean finding clonable DNA. Breathing life into the extinct woolly mammoth is likely to be a possibly impossible operation. During life, the damage to fragile DNA is repaired naturally. After death, the genetic code quickly breaks down. Siting in ice for 20,000 years, the water damage, the ultraviolet radiation and the chemical decay will likely shatter your DNA to bits.
Robert DeSalle, a curator at the American Museum of Natural History, calls this the “Humpty Dumpty” problem. These genetic fragments would likely be 10,000 to 100,000 times smaller than the DNA pieces the researchers in the human genome project are working with. Except for a simple flu virus, No organisms have been manipulated this way.
For cloning to work, you need the entire genome be completely intact. Even though an animal might be frozen for centuries, bacteria and fungi begin colonizing its tissues from the moment of death and consuming it until all is buried by snow.
Hmmm…that sounds rather condemning.
It’s confirmed by a quote from a researcher,
“While we can now retrieve the entire genome of the woolly mammoth, that does not mean we can put together the genome into organized chromosomes in a nuclear membrane with all the functional apparatus needed for life,” said Ross MacPhee, a researcher at the American Museum of Natural History who worked on the project. “We can’t even do that with modern DNA.”
But wait…there’s more. In the same article, comes this:
Other researchers have expressed a desire to revive the mammoth by injecting frozen sperm DNA — if they can find some — into elephants. Over several generations, they’d create a creature that’s 88 percent mammoth.
So, cloning outright is impractical, but creating a mostly-mammoth hybrid may be possible. (National Geographic provides more depth on this.)
How far then does this digress from species preservation and ecosystem restoration to outright experimentation? Once we created such an estimated species, if we were then to discover its behaviors were not suitable, should we pursue selective breeding to align the new creature better to the ecosystem? If not, what are the ethical questions we must ask about eliminating a new species (or subspecies, hybrid, whatever) that we have so recently invented?
Personally, I’m for the idea of creating the 88% creature, but I think that my position may be informed more by that odd human tendency toward technological megalomania than by the initial ecological altruism that turned me on to the Pleistocene Rewilding concept in the first place. (And if sentence length can be used as an indicator of moral uncertainty, then certainly that last one presents a psychological field day.)
(I hope you weren’t expecting me to have a more solid conclusion…)