With gene-editing technologies such as CRISPR, the variety in produce has been growing at greater rates than ever. It seems as if it is only a matter of time until we get a talking pepper. However, potatoes have been lagging behind. A potato may look quite simple to the human eye, but it is actually quite complex in the world of genomes. For this reason, the human genome was discovered more than 20 years before the genomes that make up a delicious fast food French fry.
So what is it that makes the potato genome puzzle so difficult to crack? Human offspring receive one of each chromosome from the mother and father, while potatoes receive two of each chromosome from each parent. This results in 4 total copies of each chromosome and in turn four copies of a given gene. A species such as this is called tetraploid. The increase in genes per trait makes editing a given trait that much more difficult. Another task of great difficulty is recreating the potato genome. A task much more difficult than doing so for humans.
Scientists Korbinian Schneeberger and Hequan Sun found a clever shortcut. They realized that the pollen cells of potatoes, similar to gametes in humans, contain only half the chromosomes of a body cell. Pollen cells are by this logic, diploid cells containing two of each chromosome. Sequencing the DNA of large amounts of pollen cells allowed the scientists to map out the full genome of a potato. The construction of this genome will make identifying and editing diverse variants of potatoes a much easier task.
This begs the question of why? Why do we need variety in species of potato? Historical events such as the Irish potato famine of 1840 are a prime example of the importance of produce variety. The famine was caused by tuber blight. A potato is a tuber, a storage stem of plats, and blight is a plant disease commonly caused by fungi. Despite being the most important crop and source of food at the time in most of Europe, the incredible lack of variability of a potato meant no species of potato was resistant to the disease. With concerns over climate change, and an increase in potato popularity; “The potato is becoming more and more integral to diets worldwide including even Asian countries like China where rice is the traditional staple food. Building on this work, we can now implement genome-assisted breeding of new potato varieties that will be more productive and also resistant to climate change — this could have a huge impact on delivering food security in the decades to come.” (Max Planck Institute for Plant Breeding Research), make this issue more important than it may appear.