by Mark Molloy
Published by NYU Press, 2013 | 258 pages
Growing up in suburban New Jersey, I was warned not to kill praying mantises. They faced extinction, the story went, and killing them was against the law. This story, it turns out, was a myth – praying mantises were not, in fact, endangered, nor does any such legal protection exist. The existence of such a myth, however, is revealing. Species extinction had, even then, seeped down into the imaginations of children. Only later did I learn of the far more vast extinction crisis currently underway, likewise caused by humans but this time very real, on pace to rival the greatest extinction events in earth’s history.
As long as there has been life, there have been species extinctions. This is part of the natural order. But in the fossil record we find evidence of something entirely more extraordinary, global extinction events of unimaginable scale. The Permian–Triassic extinction event, for example, wiped out 90% to 96% of all species on the planet. Until the arrival of homo sapiens, these extinction events were driven by cataclysmic natural disruptions such as asteroid impacts and volcanic activity. Since the arrival of homo sapiens, no such natural catastrophes of this scale have occurred, and yet we find (overwhelming) evidence that we are in the midst of another mass extinction event. Between 1500 and 2009, humans have documented the extinction of 875 species, an extraordinarily high rate compared to the average. Studies estimate that more than one million land-dwelling plant and animal species will have been driven extinct by our human population. The cause of this current extinction event, forecast to rival some of the worst in the history of our planet? Ourselves.
Conservation biology, “the scientific study,” according to Wikipedia, “of nature and of Earth’s biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions,” has arisen only in the past few decades. In Cloning Wild Life, sociologist Carrie Friese offers an account of one branch of this discipline: the recent utilization of cloning as a means of preserving endangered species. This techno-scientific approach to species survival marks a new chapter in the history of endangered species and raises profound questions as to the nature of concepts such as the “natural,” and what our role is in relation to this ever-evolving, and presently collapsing, world. Ultimately, Friese investigates how the ways in which we interpret the status of cloned individuals affects the ways in which we understand ourselves and our place in nature.
The process of cloning is simple enough, at least in theory. The DNA found in the cells of individual organisms (from amoeba to humans) contains all the instructions needed to build and operate said organisms. In “somatic cell nuclear transfer,” researchers remove the native genetic material from an unfertilized egg cell and implant the complete DNA of a separate organism to be cloned into this unfertilized egg. This egg is then implanted into the womb of an adult female of the species. The individual this female later gives birth to will have, it follows, the identical genetic material as the original DNA donor. As a scientific technique, cloning became famous in the mid 1990s when researchers at Scotland’s Roslin Institute, with the help of three “mothers” (one sheep provided the egg cell, another the nuclear DNA, and a third the surrogate uterus), produced Dolly, the first animal to be cloned via the process of nuclear transfer into an adult somatic cell. In the case of endangered species, those Friese treats here, for whom genetic materials and surrogate mothers are scarce, scientists must often resort to interspecies somatic cell nuclear transfer, in which individuals from different but closely related species are used as donors and surrogates. As you can imagine, here things get a bit more complicated.
An especially interesting, and crucial, question arises as to whether the genetic clones of individuals of endangered species should themselves be considered endangered? This question is highly debated, with at least three common answers being posited: clones are members of the endangered species that donated their genetic material; clones are not members of these endangered species; and clones may be members of these endangered species, depending on their sex. The first answer to this question, that cloned individuals are indeed members of endangered species, makes intuitive sense—they are, after all, genetic replicas of individuals within endangered species. The second answer, however, is not a trivial suggestion. It derives from the fact that in addition to the well-known nuclear DNA, cells also contain a second, and separate, line of DNA: mitochondrial DNA. (Scientists think mitochondrial DNA and nuclear DNA evolved separately, that organisms evolved directly from their nuclear DNA, and that at some point in the early history of life mitochondrial DNA hitched a ride for the mutual benefit of both genetic lines.) According to this argument, these individuals (with nuclear DNA from their genetic donor injected into cells that contain mitochondrial DNA from their egg donor) represent a hybrid species or chimeras (a makeshift term for single organisms with genetically distinct cells), which should not be accorded the status of endangered. There is an additional nuance, however, which further complicates the issue. Mitochondrial DNA, it turns out, is passed down exclusively via the female egg. And here arises the third common answer, for some argue that cloned males – who will contribute only nuclear DNA – should be allowed to breed with native endangered species populations, while cloned females – who will introduce the chimerical mitochondrial DNA into the donor species’ gene pool – should not. The offspring of the cloned male with the native female, in this reading, again joins the ranks of the endangered species.
As Cloning Wild Life is, ultimately, a work of sociology, Friese’s main interest here is in how cloning reorients questions about our human relationship with the natural world. Her analysis is timely given the robust interest in investigating the Anthropocene—a proposed new geologic period marked by our collective human ability to remake the earth—and the ways in which the human impact on the environment blurs the boundaries of traditional designations like nature and culture. What impact, Friese asks, does any decision to classify clones as endangered species or to deny them this right, have on our human self-conception? What are we to make of, and do with, our newfound, “godlike” ability to not only save species from extinction, but even bring extinct species back to life? These are crucial, urgent questions, and ones sure to grow even more pressing and essential, to conservation biologists as well as the wider public, as we continue to refashion our world.
Brian Tyrrell is a graduate student in the Department of History at the University of California, Santa Barbara. He studies environmental history and the history of science.