New research reveals major difference in genomes of American and Chinese chestnut

The chromosomes of American and Chinese chestnut are not so similar after all, at least in one key region of the genome—the nucleolus organizing region (NOR).The finding, published in Scientific Reports, has major implications for anyone with the goal of conferring blight resistance to American chestnuts through hybridization with the Chinese chestnut."This is an unprecedented finding in the field of plant cytology," says Nurul Faridi, a Forest Service geneticist and lead author of the study.Traditional backcross breeding, involving hybridization between two species, aims to combine an ideal mix of traits from two species without genetic engineering. Backcross breeding can only succeed when the chromosomes of both species are compatible. Because Chinese-American chestnut hybrids are viable, people have assumed that the two species are highly compatible. But the new study reveals significant differences in the NOR of the two species.The NOR is part of every plant and animal cell. ...