Abstract
Haploid cells are excellent tools to study gene function as they contain a single copy of the genome and are thus unable to mask the effect of mutations. Recently, haploid embryonic stem cells, which are capable of self-renewal and potentially differentiating into other cell types despite having only one set of chromosomes, have been established in several species. These unique haploid cells allow us to seek recessive gene functions in mammals, and have had a profound influence on the field of genetic screening and drug target identification. In this review, we briefly introduce advances and breakthroughs in haploid cell line research and broadly discuss the versatile application thereof.