Sequencing a Juglans regia × J. microcarpa hybrid yields high-quality genome assemblies of parental species

Abstract

Crop genetics: lessons from hybrids The genetic sequence of a hybrid walnut tree sheds light on the evolution of the parental species and on some important traits. A study led by Ming-Cheng Luo and Jan Dvorak at the University of California Davis, USA, describes a new approach for producing high-quality genome assemblies of the parental species from interspecific hybrids. By applying long-read sequencing technology and optical mapping to a popular hybrid between cultivated Persian/English walnut and a wild relative that is native to North America they were able to completely assemble the genomes of these two species, gain insights into the evolution of their chromosomes and the distribution of disease-resistant genes. This approach could be used on other outcrossing crops to generate reference-quality genome assemblies and accelerate genetic improvements in commercially important crops.