Genomic analysis of 6,000-year-old cultivated grain illuminates the domestication history of barley
An international team of researchers has succeeded for the first time in sequencing the genome of Chalcolithic barley grains. This is the oldest plant genome to be reconstructed to date. The 6,000-year-old seeds were retrieved from Yoram Cave in the southern cliff of Masada fortress in the Judean Desert in Israel, close to the Dead Sea. Genetically, the prehistoric barley is very similar to present-day barley grown in the Southern Levant, supporting the existing hypothesis of barley domestication having occurred in the Upper Jordan Valley.
So far, most of the research of archaeobotanical findings has been limited to a comparison of ancient and present-day specimens based on their morphology. "The fact that we were able to map out the genome of 6,000-year-old barley grains allowed us, for the first time, to receive a more reliable picture of the source and the domestication process of the barley that played a major role in the agricultural revolution and the transition from a Hunter-gatherer society to an agriculture based one", the researchers say.
Sequencing and producing ancient DNA from 6,000 year old grains is not trivial, since the DNA broke into little pieces of only 20-70 letters. "Reconstructing the barley genome which consists of about 5 billion letters from such short sequences is like trying to reconstruct an old clay vase that broke into a million tiny little pieces. However, using the genomic technologies available today and powerful computers, we were able to virtually reconstruct those small DNA sequences into large parts of the genome in a way that allowed us to understand the genome as a whole" explains Dr. Sariel Hubner, a new researcher at the Galilee Research Institute (MIGAL), who has addressed the bioinformatics and genomics aspects in the project. Dr. Hubner’s research focuses on quantitative and population genomics mostly in crop plants and their wild relatives. “Our findings indicate that the domestication of barley, which is now days cultivated around the globe, has started here in the upper Galilee. In fact, the strongest signal was obtained near Kibbutz Dan”. These findings further support the importance of scientific research in the upper Galilee and the importance of agriculture in this region since its very beginning.