The orange is a hybrid between pomelo (Citrus maxima) and mandarin (Citrus reticulata). It has genes that are ~25% pomelo and ~75% mandarin;however, it is not a simple backcrossed BC1 hybrid, but hybridized over multiple generations. The chloroplast genes, and therefore the maternal line, seem to be pomelo.The sweet orange has had its full genome sequenced. Earlier estimates of the percentage of pomelo genes varying from ~50% to 6% have been reported.