Attendees at the Tūranga Speaker Series event on Monday April 10th were in for a fast-paced night of biochemistry, population biology, and new technologies, all explained by University of Canterbury Genetics professors Tammy Steeves and Jack Heinemann.
Professor Jack Heinemann kicked off the discussion by posing the question: “Is the future of gene technology in the Gene Technology Bill 2024?”—a kōrero around the proposed new bill that, if passed, would reshape the genetic engineering framework in New Zealand.
We were introduced to the Hazardous Substances and New Organisms Act (HSNO), which currently regulates genetic technology. Under this Act, gene technology can be used in registered containment facilities and any GMOs made can be tested in field trials or released for use in the environment, medicine, or food. The process involves modifying biological material in a containment facility, selecting for the desired traits, followed by an evaluation and risk assessment through laboratory and field tests before any large-scale release.
This framework has served to ensure that what is made using gene technology causes no harm to New Zealand. This safety net could be removed just when it is becoming possible for anyone to access the tools of gene technology. For example, during the COVID-19 pandemic at-home CRISPR-Cas9 kits (a specific and powerful enzyme-driven gene editing technology) were “made in professors' garages, straight to students’ kitchens” in the US. This was a new way of doing things, and marked a significant shift from the previous containment model.
Jack then addressed an argument which has been proposed in favour of the Bill — that New Zealand is falling behind other countries, particularly its trading partners. Upon comparing genetic technology laws globally, he pointed out that most countries don’t implement blanket deregulation. Instead, gene editing must still be done within containment facilities by trained professionals. In fact, all of our top 10 trading partners have stricter regulatory frameworks. Therefore, passing this Bill wouldn’t just bring us in line with the rest of the world — it would put us out of step with it. The question was posed by an audience member in the Q&A — do we need to be?
Jack elaborated on a key component of gene editing: site-directed nucleases (SDNs). These enzymes act like molecular scissors, creating double-stranded breaks in the DNA molecule. Theoretically, SDN1 reactions only cut the molecule without adding foreign DNA. SDN2 reactions attempt to introduce similar DNA, while SDN3 reactions add transgenes so dissimilar they can be considered to be from different species, and are considered “high-risk”. However, even SDN1 reactions can lead to unexpected outcomes. Even in a containment facility, the nature of genetic technology means there is a high risk of unintended transgene insertion. Jack highlighted the example of hornless cows, modified by Recombinetics in the US. What was initially hailed as a breakthrough in genetic technology turned problematic when sequencing revealed over 4,000 nucleotides of bacterial plasmid DNA—making the cows transgenic organisms, part bovine and part bacterium. This was a supposedly low-risk SDN1 reaction — which New Zealand could deregulate — used in a sterile containment facility by trained professionals, and highlights the unpredictable outcomes of this technology.
Jack concluded his section of the kōrero with a stark warning: “What gives that famous precision to gene editing technology? Laws.” A thought-provoking reminder about the ethical and regulatory considerations in gene editing.
Professor Tammy Steeves then took over, delving into how genetic technologies and genomic data could be used to save endangered species. She began with a foundational concept in population biology: alleles, or variations of a gene. Tammy used the analogy of a jigsaw puzzle: the entire genome is the puzzle, and a gene is one piece. These pieces can come in different colours, much like how a gene for flower colour in Mendel’s peas can be purple or white. These two colour variants are alleles (variants) of the same gene.
High genetic diversity, or when there are many different alleles within a population, leads to a “healthier” population which is better able to adapt to environmental changes. Endangered species often have low genetic diversity. This typically occurs when a species' population shrinks due to environmental or human impacts. As individuals die off, their alleles are lost, creating a “gene puddle” instead of a gene pool. This limits the species' ability to adapt and increases the risk of accumulating harmful alleles, which can further reduce reproduction and increase the risk of extinction.
Tammy connected this issue to how genetic technologies might help endangered species. By studying genomic data, it may be possible to introduce new or lost alleles into an endangered population to reduce extinction risks. Could the "de-extinction" of the dire wolf by Colossal Biosciences offer a model for Aotearoa? Might we someday soon see populations of moa roaming wild valleys? While the prospect is exciting, it’s not that simple.
Colossal Biosciences does intend to use this technology to introduce lost alleles into species nearing extinction. The pink pigeon, a species from Mauritius, is a prime example. In the 1970s, only 12 pigeons remained. After intensive captive breeding and reintroduction efforts, there are now about 500. However, the genetic diversity in this population is low, and there is a high frequency of harmful alleles. Through genomic sequencing of eggs, bones, and skin from pink pigeon remains in museums, scientists could theoretically find lost alleles to reintroduce via primordial germ cell editing. However, there’s a challenge: how do scientists know which alleles to introduce? The traditional Mendelian model of inheritance is oversimplified for such complex processes. Even the creation of the “dire wolf” follows a morphological species concept — meaning that there was a focus on editing “big-impact” genes which affect how a species looks. Often, a combination of many “low-impact” genes are associated with reproduction and survival, and these are notoriously hard to find. For the focus of gene editing to be less about how a species “looks” and more about how it survives in an environment, the lens needs to be shifted towards searching for the many genes which work together to control these complex processes.
Moreover, even if the genes could be found and edited into the genome, the risk of losing them is high. Many birds would need to be genetically modified, and the population would need to grow. It seems a very expensive and time-intensive process to go through for no guaranteed reward of species survival. Tammy concluded by reminding us: “If something seems too good to be true, it probably is.” Her optimism lies in the collaboration between conservationists, iwi, and community groups to preserve Aotearoa’s unique species rather than relying on futuristic genetic fixes.
Read more
- Explore the Christchurch City Library network catalogue for books on Genetics.
- Find books on Biodiversity Conservation.
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