In a new study, a team of scientists at the University of California, Davis, and USDA’s Agricultural Research Service (ARS) used a unique approach to sequence the genomes of the English walnut and its wild North American relative by tapping into the capabilities of two state-of-the-art technologies: long-read DNA sequencing and optical genome mapping. The resulting genome sequences are believed to be of the highest quality ever assembled of any woody perennial.
“By sequencing the genome of a walnut hybrid, we produced complete genome sequences for both parents in the time normally required to produce the sequence of one genome,” said Ming-Cheng Luo, leading genomics investigator on the project and a research geneticist in the Department of Plant Sciences at UC Davis.
This approach could be applied to genome sequencing of trees and many other woody perennials, opening the door to a better understanding of the genetic blueprints of almonds, pecans, pistachios and grapes.
The assembled genome sequences of the two walnut species also will now help researchers identify genetic markers that breeders can use to develop new varieties with improved pathogen and pest resistance.
Tingting Zhu et al. Sequencing a Juglans regia × J. microcarpa hybrid yields high-quality genome assemblies of parental species, Horticulture Research (2019). DOI: 10.1038/s41438-019-0139-1