Gene Banks: Preserving the Past for the Future

Biological diversity occurs at three different levels:

  1. At the ecosystem level, biodiversity exists in the form of different combinations of species and the interactions between them
  2. At the species level, biodiversity is related to the number of different species
  3. Within a species, biodiversity refers to genetic diversity

Genetic diversity gives species the ability to adapt to changing environments, including pests, diseases, and climate change. This section is mostly concerned with conserving these valuable genetic resources so that they are available for use and study in the future. There are two main approaches to maintaining genetic diversity: in situ conservation and ex situ conservation. In situ conservation is concerned with maintaining species within their natural environments. Ex situ conservation comprises of methods that maintain the genetic integrity of collected germplasm samples outside their natural habitats. Genetic resources that are maintained outside of their natural habitats and managed under artificial conditions in facilities are known as gene banks.

How is the Creation of Gene Banks Going to Help Preserve Biodiversity?

  1. With plants, unfreezing preserved material and artificially propagating it can be used to regrow chosen plants. This could be used if the need arises to save an endangered plant species.
  2. Though artificial insemination in mammals has been successful, a living female is required. Preserving mammalian sperms would allow for in vitro fertilization and surrogacy if the need arises to save a particular mammalian species.
  3. More importantly, collecting the genetic master plans for the planet's animals and plants makes it easier to study the workings of the natural world. By studying the DNA of animals, scientists can deduce which genetic traits of those animals enable their survival. With that information, researchers can cater conservation actions to address these traits. Secondly, scientists may be able to use genetic engineering to make plants and animals more adaptive to the coming climate changes and perhaps even resistant to disease breakouts. This could also be used to save species from extinction.

Methods for Creating Gene Banks

One method of creating seed banks involves drying and freezing seeds at temperatures that are more or less on par with a typical winter temperature. Some seeds can survive in this state for decade, but all eventually require thawing and re-growing to provide fresh, vital seeds. However, if the seeds are frozen at lower, cryonic temperatures, all molecular motion comes to a halt. While the second method is more expensive than normal freezing, it vastly increases the shelf life of a plant's genetic material. In order to approximate the funds required to establish seed banks, we used a case study on the Svalbard Global Seed Vault. Construction of the seed vault cost approximately 45 million Norwegian krones (9 million USD) and was funded entirely by the government of Norway. The storage of seeds in the vault is done free of charge. Depositng seed samples in the Svalbard does not amount to a legal transfer of seeds, and hence, genetic resources. Any private company or government that deposits seeds signs a deposit agreement with NordGen, a group acting on behalf of Norway, that states that Norway does not have ownership of the deposited samples and the the ownership remains with the depositor. The depositor then has sole access to the deposited materials. Operational costs are paid by the government of Norway and the Global Crop Diversity Trust. Primary funding for the Trust comes from private and non-profit organizations, such as the Bill & Melinda Gates Foundation, and from numerous governments worldwide.

For animals, the procedure is slightly more complex and requires freezing sperm and eggs in zoological freezers. There are two important developments that aid in this process. The first was the creation of a new culture media system that protects the egg from damage during the freezing/thawing process. The media system dehydrates the egg during freezing and rehydrates the egg during thawing, thereby minimizing the formation of ice crystals. The second breakthrough was a fertilization technique known as ICSI (Intra-Cytoplasmic Sperm Injection). With ICSI, the embryologist injects the egg with a single sperm to fertilize it. The zygote is then frozen, which can greatly increase the life of the egg and sperm. Egg freezing is still being investigated by the American Society for Reproductive Medicine. By using these new advances in cryopreservation, scientists have seen a sharp increase in post-thaw survival rates (as high as 90 percent) and fertilization rates (as high as 80 percent). To further investigate the prospects of creating a gene bank, we investigated a cryopreservation bank that was established in 1972 at the San Diego Zoo in California and contains DNA samples from endangered animals. The "Frozen Zoo" stores living samples of skin tissue, embryos, sperm, and eggs from 800 species of animals that are not far from extinction.

Our main proposal is to create genomic libraries for as many species as possible by mapping their genomes. The focus would be first on those species that are endangered or threatened. Even though the Human Genome Project took years to complete and required funds of 3 billion USD, the method for genetic mapping has since been modified and is now much less time and labor intensive.

The current Genome 10K project further exemplifies the above proposal. The project aims to assemble a genomic zoo, or a collection of DNA sequences that represents the genomes of 10,000 vertebrae species, or approximately one species for every vertebrae genus. The trajectory of cost reductions in DNA sequencing suggests that this project will be feasible within a few years, and it is expected that the project will need no more than 50 million USD to complete. The Genome 10K Community of Scientists (G10KCOS) is made up of leading scientists that represent major zoos, museums, research centers, and universities around the world. G10KCOS is dedicated to coordinating efforts in tissue specimen collection that will lay the groundwork for a large-scale sequencing and analysis project. The i5K project, inspired by the 10K project, was initiated in March 2011 and expects to sequence the genome of 5,000 insects and related arthropod species over the next 5 years.

The initiation of several such individual projects with specific agendas for specific progenies could lead to the creation of a "master genomic library". Such a library could, in later years, help scientists determine the best strategies to save endangered species and would aslo serve as unprecedented resource for the life sciences and for worldwide conservation efforts.