Next-generation sequencers are transforming animal breeding, enabling cost-effective whole-genome sequencing and resequencing studies to identify genetic markers over the entire genome. Genomic selection (GS) is a marker-assisted selection method, in which markers covering the whole genome are used simultaneously for individual genetic evaluation via genomic estimated breeding values (GEBVs). GS is becoming the major genetic evaluation method for all livestock species and may soon completely replace the traditional genetic evaluation system. In recent years, GS has become an important research topic in animal, plant and aquiculture breeding.