Where does our food come from?
About 10,000 years ago, humans began taking over control of the reproduction of the organisms they relied on for food. This process, called domestication, dramatically changed the course of human evolution as we began the switch from hunting and gathering to farming. Archaeologists, anthropologists, linguists and geneticists all contribute to putting together the story of when, where, why and how this process took place. Our research group contributes to this effort by looking at the genetic codes of various crops, especially grapes and apples. The sequence of letters of the DNA code can be read like a book and we use modern statistical techniques to interpret each crop’s book of DNA, i.e. its genome. By deciphering these genomes, we not only gain insights into the history of our relationship with food, but we also help better manage our future food supply.
How do we make better food?
When humans made the switch from hunting and gathering to farming, we began controlling the reproduction of plants and animals that we rely on for food. Along with our decision to control the lives of these plants and animals comes the responsibility of preserving their diversity and using it wisely to breed better food. Today, almost every object that appears on our dinner plates is the end result of a breeding programme in which specific traits were selected for decades or sometimes even millennia. But breeding is not just an important part of our history, it is also an essential part of our future.
Traditionally, when breeders aim to generate a new cultivar (plant selected for desirable characteristics), they choose parents with desirable traits and make them reproduce. Often, hundreds or thousands of the resulting offspring are grown, but only a select few will be deemed worthy of commercial use. While this process has generated most of the food we enjoy today, it is also laborious, time-consuming and expensive.
Our research aims to help make the breeding process more efficient and cost-effective by helping breeders decide which offspring to keep and which offspring to discard. We are doing this through marker-assisted selection, which uses DNA sequence information (i.e. genetic information) to guide the breeding process. We are not making genetically modified organisms (GMO’s) – we are just trying to figure out what constitutes a desirable genetic profile and what does not. To do this, we are determining which DNA variants in apple trees are associated with desirable traits, such as sweetness/acidity balance and disease resistance, and which are not. We are doing this research by measuring traits and sequencing the DNA of apple trees in the Apple Biodiversity Collection (ABC), which contains over 1300 diverse apple cultivars planted here in Kentville, Nova Scotia. The data we collect and the methods we develop will enable breeders to predict what apples will taste and look like before trees are fully grown, which promises to dramatically improve the efficiency of apple breeding. Our aim is to help breeders more efficiently make use of nature’s tremendous natural diversity to develop food that is desirable and requires less chemical input to grow.
The food we are making
We love Nova Scotia wines. But we have heard from grape growers in the province that a particular grape variety, called New York Muscat, is low-yielding and arduous to grow. So, this past summer we started a breeding programme to generate an improved muscat grape variety right here in Nova Scotia. We crossed New York Muscat with Nova Scotia’s quintessential grape, L’Acadie Blanc, and generated about 1700 seed. We know from previous work that the muscat aroma in grape is caused by a single variant in the grape’s DNA. So, we will allow the 1700 seeds to grow into seedlings in the greenhouse and will then extract DNA from a small piece of their leaves. From the DNA, we will determine whether a seedling carries the DNA variant that causes the muscat aroma. Those that do not carry the variant will be thrown away at the seedling stage. Those that do carry the variant will be planted out in the vineyard and will be evaluated for various characteristics (e.g. yield, flavour, disease resistance). This process is called marker-assisted selection and it makes the breeding process far more cost effective and efficient. After many years of evaluating the resulting grapes, we hope to release a new muscat variety to grape growers and winemakers in Nova Scotia and beyond.