The use of selectable marker genes, such as the kanamycin resistance encoding neomycin phosphotransferase (nptII), has been invaluable in transgenic plant production. The subject invention provides a new selectable marker gene, an Arabidopsis thaliana ATP binding cassette (ABC) transporter, Atwbc19 and methods of using the gene for the identification of transgenic plants. Since ABC transporters are endogenous to plants, there should be less controversy using Atwbc19, as a selectable marker in transgenic plants with regards to concerns of horizontal gene transfer.