Gene Variation within a Tree

The root system of a tree species is genetically different than the leaves of that individual, potentially modifying scientists’ understanding of evolution.

Aug 13, 2012
Edyta Zielinska

Sequencing the genomes of tissue taken from the entire black cottonwood tree, from their crowns to their roots, researchers at University of Illinois at Urbana-Champaign found over a hundred thousand mutations that were unique to a particular tissue sample, differing from other parts of the same tree.

“This could change the classic paradigm that evolution only happens in a population rather than at an individual level,” said Brett Olds from University of Illinois at Urbana-Champaign, a biologist from the Ken Paige lab that presented the work at a meeting of the Ecological Society of America, according to Nature.

The black cottonwood was chosen for the study because it lives up to 200 years and can produce offspring via new shoots that share the same root system as the parent. While clonally reproduced organisms often share a majority of their genes, the researchers found more similarity between the tops of two different trees than there was between the top and bottom of the same tree. “When people study plants, they’ll often take a cutting from a leaf and assume that it is representative of the plant’s genome,” Olds said. “That may not be the case. You may need to take multiple tissues.”