Biobanks save endangered species and preserve biodiversity

The value of wild animal biobanks and reproductive biotechnologies

Understanding and sustaining a biodiverse planet is a critical task. Historically, genetically diverse species have been preserved by protecting large-size natural habitats, a strategy that, while ideal, is insufficient given our growing global human population that now exceeds 7 billion people. Resource demands by humans doom the idea that all species can survive sustainably and undisturbed in nature. Zoos and aquaria are not the answer due to severely limited spaces in their restricted urban environments - too few acres to manage enough animals. This is now fact as most structured breeding programs in zoos are failing to meet demographic and genetic goals, including retaining at least 90% of existing gene diversity (Monfort, 2014). Thus, while governments determine how to protect and restore habitat, and zoos explore alternative conservation approaches (for example, the advantages of large breeding centers; Wildt et al., 2012), there is a crucial unfilled gap - protecting the extant genomes of living species that already are under threat, or are likely to be so soon.

This need actually may be envisioned as an enormous opportunity that can be addressed by establishing and using wildlife biobanks - organized collections of living biomaterials. The value of maintaining data-rich biological samples, including microorganisms, DNA, somatic cells, tissues, blood products, germplasm and embryos, has long been recognized for human health care and agro-industries and is a fundamental component of most basic scientific research (Baker, 2012).

The idea that these genome banks should exist for more than humans, livestock and crops is not new. The U.S. National Academy of Science declared in 1978 that ‘what is done for domestic species should be done for all species’. Similar proclamations also were made decades ago by the U.S. Agency for International Development, the U.S. Congress’ Office of Technology Assessment and the National Science Foundation. Subsequent advocacy and sound justifications have been provided by various laboratories (Comizzoli et al., 2012; Comizzoli and Holt, 2014). First, there is the ‘insurance factor’, that is, protecting what we have now - all species and all existing gene diversity. Small populations of endangered species are especially vulnerable to events beyond inbreeding depression, including environmental catastrophes and epidemics. This is especially relevant as most of the earth’s biodiversity exists in underdeveloped regions that are particularly sensitive to epizootics and drastic shifts in social and political structure. These resources deserve immediate and thorough protection. Second, having repositories of biomaterials, especially germplasm, can support conservation breeding programs where the goal of producing healthy and sustainable insurance populations is only possible in the face of adequate gene diversity. Currently, such programs exclusively rely on the expensive and unsafe movement of wild animals from one zoo to another for breeding. With biobanks and assisted reproductive technologies (i.e., artificial insemination [AI] and embryo transfer), only germplasm and embryos are moved to maintain the same levels of heterozygosity. Availability of germplasm in the repository also extends the generation interval of individual animals indefinitely, to be rederived and infused into the living population at any time, 5, 20 or more than 100 years from now. The result is decelerating natural losses in diversity as a result of genetic drift. At the same time, managing a portion of the species as frozen germplasm reduces space needs. For example, even partial reliance on AI with frozen semen could reduce the number of living animals required in zoos and breeding centers by as much as 50% (Wildt et al., 2010).

There now are real-life illustrations of using biobanks for conservation breeding. The iconic giant panda is routinely managed in ex situ collections and on a large-scale in China using AI with fresh and frozenthawed spermatozoa (Comizzoli et al., 2009). The black-footed ferret, once the most endangered species in North American, has been recovered by a combination of natural mating and AI [artificial insemination] (Howard and Wildt, 2009), including with sperm that has been frozen and stored for up to 2 decades. A litter of cheetah cubs was produced in a North American zoo by importing frozen sperm from a wild captured male in Africa (Comizzoli et al., 2009). There also are many examples of ‘milestone’ births using frozen-thawed spermatozoa or even embryos (Saragusty and Arav, 2011; Comizzoli et al., 2012) with the incidence of success completely dependent on having an excellent understanding of the details of the target species’ reproductive physiology (Wildt et al., 2010; Comizzoli and Wildt, 2013).

The components of the most valuable wildlife biobanks, of course, extends beyond reproductive cells to include tissues, cell lines, blood products and DNA, all highly relevant to the study and maintenance of biodiversity. Quantifiable amounts of genetic diversity can be determined for every sampled individual to help make informed conservation management decisions as well as improve our understanding of the processes underlying patterns of gene flow, selection and mating (Comizzoli et al., 2009). Blood samples can be screened for clinical chemistries to provide new data on species norms or as sentinel information to identify onset and, eventually, cause of disease outbreaks to speed remedial actions. Most importantly, properly organized biobanks can provide open access to qualified researchers who normally work outside the conventional mainstream of wildlife conservation biology. This has the potential for generating vast amounts of additional basic and applied information, especially as advantages of the new ‘omics’ technologies are realized and directed to stored samples. Genomes of thousands of organisms, including bacteria, archaea and many fungi, animals and plants have been sequenced to begin more thoroughly documenting the earth’s abundant bio- and genetic diversity (Tanabe and Toju, 2013). Genomic data are being annotated, augmented and refined through transcriptomics, proteomics and metabolomics to give us detailed pictures of messenger RNA, protein and metabolite systems and the mechanisms that are controlling life (Baker, 2013).