Wednesday, 29 October 2008

Requiem for a Culture

When the world’s first clone, Dolly the sheep, took her first tentative steps, some more lateral thinking conservationists might be forgiven for having imagined that this new technological triumph could well herald the end of extinction. For what better way could there be to immortalise a species under threat than to sequence its gene in their entirety and simply clone new individuals on demand. So long as tissue or blood samples could be taken from an ailing species, they could even be frozen and preserved long after the extinction of a species, simply waiting for the technology to catch up. Of course some manner of artificial womb or surrogacy system would be needed in order to create a viable and reproducing population of adequate size, but to imagine that such technical hurdles could be overcome would not at all be unreasonable. The problem of premature ageing that faced poor Dolly is also unlikely to be an insurmountable obstacle. Despite all of this, I suspect there is in fact something that will stand in our way, something much more difficult to replicate than mere DNA.

Our understanding of evolution has perhaps led us to think in too narrow terms about what it is that makes a species. It is certainly conceivable that the technology that created Dolly could well become streamlined and commonplace enough to be applied to almost any species, but is that in fact enough to return a species from extinction? Consider the case of the curiously named Poʻouli, a bird native only to Hawai’i. Tragically, for those who consider biodiversity to be of benefit to the world, the last known individual of the species died whilst biologists attempted to locate a possible female still in the wild. Tissue samples were taken from the male before its death in the hopes that developments in cloning technology might one day revive the species. Of course, without samples from a female, it is debatable as to what good cloning males will do. But this is not the greatest impediment to resurrecting the Poʻouli. After all, we know biochemically and genetically what sets male and female apart. At a push, we might be able to engineer a female based on the male genome. But when we finally manage to create the new generation of Poʻouli hatchlings, who will they look to for guidance?

That might sounds like a pretty odd question to ask about birds. But of course, imprinting upon a parent animal is extremely important for hatchlings to develop normal behavior; in many repects they learn how to be birds from their parents, who learned from their parents. Whilst we’ve managed to emulate imprinting for some endangered species of wild geese by doing clever things such as having them fly alongside people in hang-gliders, it is questionable just how well we can emulate the imprinting behavior and training of a species we can no longer study. Imprinting in birds is just one example of the countless forms of learning that are seen throughout animal species. Although it would probably not be a popular application of the term I view this non-genetic inheritance as the simplest form of culture. And in my view, even simple culture is no trivial component of any species. Of course we tend to think of culture as a strictly human phenomenon and certainly our species demonstrates just how complex culture can become. From the simple act of imparting knowledge between countless generations, we have gained everything from agriculture to religion and of course science. I am quite sure that many of the primatologists studying our closest animal relatives would not hesitate to extend the concept of culture beyond humans.

So although we have genetics in the bag, it is culture that potentially becomes irrecoverable whenever a species becomes extinct. The day an extinct species is reborn, how do we know they’re behaving as they used to? Will the Poʻouli species actually be restored if we clone a thousand chicks, raise them by hand and release them? To this day we are discovering new facets of the cultural inheritances of many species, even in those species that ought by now to be well-known to us, such as chimpanzees. Of course, for “simple” species such as birds and the smaller mammal species, it may be that we could restore a viable culture by simply cloning large numbers of individuals and allowing random behavior, time and pure natural selection to do their work. After all, cultural elements, like genes, are subject to a form of evolution. Those that confer advantage will be inherited at a higher rate than those that do not. This is something like Dawkins’ meme hypothesis, albeit extended to all life forms capable of learning. But how will we know if the emergent culture really resembles the original? The problem really is our lack of knowledge of the “memetics” of the species. While we may sequence a genome, even store it as pure computer data for later replication, how do we so accurately measure the culture of a species?

Behavioral biology is of course the field that provides our answers, but there’s no escaping the realization that what we are struggling with is something far less tangible than genes, and far more open to human ignorance or misinterpretation. In the 35 years that biologists had to observe the Poʻouli, can we be sure that every aspect of their simple culture was studied? Can we be sure that every nuance of their social interactions was even noticed? This is the intimidating challenge that really faces conservationists. With so many species now endangered, the task at hand is staggering. We may have to accept that no matter how much DNA we sample and sequence, species such as the Poʻouli, the Dodo, the Golden Toad and the Tarpan are lost to us in a manner we probably couldn’t have measured when they still lived.

Po'ouli image courtesy of the United States Federal Government under the terms of Title 17, Chapter 1, Section 105 of the US Code. Obtained from Wikipedia.

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