New DNA Study
January 8, 2010
With the planet's various environments changing at a rapid pace, the ability of species to adapt to their surroundings is being overtaken by events, and they are dying off. But how rapidly do organisms evolve? Breakthroughs in DNA technology - and especially a 10,000-fold decrease in the cost of genome sequencing - are making this easier than ever to measure.
Deutsche Welle spoke with Stephan Ossowski, one of the scientists from the Max Planck Institute involved in a recent research project, and a lead author of an article on the subject in the journal Science.
Deutsche Welle: Tell us about the basic premise behind your research.
Stephan Ossowski: The idea is that genetic mutations are the raw material of evolution, and species can only evolve if the genome is constantly changing by mutation.
We think that knowledge of these mutation processes is indispensable for understanding the process of evolution and inheritance. That includes genetic disease and cancer. The basic process underlying that is always mutation.
Why did you choose the plant that you did? It was a kind of mustard plant, right?
Yes. It's Arabidopsis thaliana, also called thale cress. It's a mustard plant and it has been the main model organism for plants for a lot of years.
It was already completely sequenced in 2000, so we have had the genome for almost 10 years now, and it's easy to grow.
When Darwin first came up with the theory of evolution he expected changes in species to occur very gradually over thousands of years. Does your research reveal things that he couldn't have guessed?
When we looked at these five plants over 30 generations, we found about 25 new mutations in each of the plant lines, which means about one per generation. On the first look this doesn't seem like that much, but considering we have millions of these thale cress on our planet, we probably have each possible mutation of each position of the genome in existence somewhere on the planet.
Taking this frequency and looking at millions of plants or millions of people – even billions of people – you can expect there are a lot of mutations floating around. So if you translate this to humans, it means each human has about 60 mutations that were not present in their parents.
Do your findings suggest any positive news for species to adapt to things? Especially I'm thinking here about climate change. Or are environmental changes like that happening far too swiftly?
If you look at the large number of plants – breeders will find every mutation that has the potential to increase the yield or make the plant more resilient. You just have to look at enough plants to find this specific mutation. And the same is true in terms of plants being able to adapt to climate change. If you have mutations that are specifically good such as drought resistance or more resistance to salt, then these will possibly survive better in the new climate.
In general, how easily can your findings be applied to other species?
We were focusing on plants, but in parallel there were other studies in flies and in worms and in yeast. They all come to the same range of mutation frequency, so this can be translated to other species as well.
Could this research have practical repercussions for humans?
(An explosion in this type of research) will also lead to the sequencing of thousands of cancer patients in coming years so that we learn for each cancer if there are possibly specific reasons for them in the genomes. We will be able to see if there is a specific mutation in the genomes which can be linked to a specific cancer in a specific patient.
What does your research tell us about, say, our evolutionary past?
This is one field where these new and more accurate estimates can help us a lot. We can construct phylogenetic trees and ask when a species split up. Or, for instance, we can ask when the domestication of plants occurred. The same can probably be done in all other species, but we haven't done this yet. You could also do so for humans.
Interview: Nathan Witkop (gps)
Editor: Jennifer Abramsohn