The characterization of a chicken homeobox gene that contains a homeobox sequence belonging to the cad family of homeodomains (the homeobox-translated region) is described. CHox-cad genomic and cDNA clones were isolated and analyzed. Northern and in situ hybridization analyses revealed that the CHox-cad gene probably encodes a single transcript of 2.6 kb that first appears in epiblastic cells when gastrulation begins, in the primitive streak, and in definitive endoderm. At later stages of development, CHox-cad is expressed in the endodermal lining of the developing gut. In addition, one target site of CHox-cad was identified. The idea of a possible role of homeobox genes in regulating quantitative traits (QTs) was examined in layer-cross and broiler populations, using CHox-cad as a probe. The results of this study revealed significant marker associations with several QTs. In order to further characterize CHox-cad regulation and the effects of its ectopic expression in the chicken, we have started to produce transgenic chickens using sperm cells as vectors. Some properties of the buffered semen diluent that is used in these experiments are described.