Study highlights genome variation
New research from German and American researchers has highlighted the large variation found in the genomes of individuals of the same species. Easy to grow and with a short life cycle, Arabidopsis thaliana has been used by biologists to study the fundamentals of plant science for years. It also has a relatively small genome, and this was sequenced in 2000. However, wild A. thaliana plants look very different from the strain that is commonly grown in labs. Writing in the journal Science, the scientists explain how they analysed the genomes of 20 different strains of A. thaliana and studied which genes were the same across the species and which genes showed the greatest differences. 'We found that one out of 10 genes is very different,' said Detlef Weigel of the Max Planck Institute for Developmental Biology. 'This plasticity is truly surprising for a genome that's very streamlined and unlike bigger genomes doesn't contain a lot of junk DNA.' The study revealed that genes involved in basic cellular functions such as protein production or gene regulation show little variability. In contrast, genes which are involved in regulating the plant's interactions with the environment and other organisms are highly variable. These are the genes that, for example, help the plant to fight off pathogens or cope with excess heat or drought. 'The genetic variability appears to reflect adaptation of local circumstances,' explained Professor Weigel. 'By extending these types of studies to other species we hope to help breeders to produce varieties that are optimally adapted to rapidly changing environmental conditions.' Professor Weigel is already working with the International Rice Research Institute (IRRI) in the Philippines to apply the methods used on Arabidopsis to 20 rice varieties. The research also raises questions about the value of model genome sequences. 'There isn't such a thing as the genome of a species,' added Professor Weigel. 'The insight that the DNA sequence of a single individual is by far not sufficient to understand the genetic potential of a species also fuels current efforts in human genetics.'
Countries
Germany, United States