The Lbx or ladybird gene family is named after the two tandemly arranged ladybird genes in Drosophila: ladybird early (lbe) and ladybird late (lbl). These form part of the NK or 93DE homeobox gene cluster (Jagla et al. 2001). In humans, there are also two Lbx genes, but these are on different chromosomes and were generated by genome duplication at the base of the vertebrates. Amphioxus has a single Lbx gene. The NK gene cluster has broken in chordates (Luke et al. 2001). Lbx genes are usually physically adjacent to Tlx genes.|
Jagla K, Bellard M, Frasch M (2001) BioEssays 23: 125-133.
Luke GN et al. (2001) PNAS 100:5292-5295.