Deleterious mutations are characterized by higher genomic heterozygosity than other genic variants in plant genomes

Deleterious mutations can reduce the fitness of crop varieties, which limits the plant breeding efficacy. While crop deleterious mutations have been extensively examined, most studies focused on one specific crop with different analyzing methods, which hinders unveiling shared genomic characteristics of deleterious mutations across diverse crops. Here we used standardized approaches to characterize the deleterious mutations in genomes of domesticated inbreeding (i.e., rice, soybean, and tomato) and clonally propagated crops (i.e., grape and pineapple). We found that deleterious mutations are commonly targeted by purifying selection, and are over-presented in a nearly fixed derived allele frequency in the course of plant domestication. Further, a generally negative correlation between genetic load and the artificial selection strength is observed. Importantly, we consistently uncovered the higher derived genomic heterozygosity for deleterious mutations compared to other genic variants. This study broadens our understanding of the evolution of deleterious mutations in plant genomes.