Chromosomal assignment of R-spondin genes in the donkey (Equus asinus, 2n = 62)

R-spondins constitute a recently discovered small family of growth factors, and the evidence of their role in several developmental pathways is growing fast. In this work we describe the chromosomal location of the fourRSPO genes in the donkey. Using horse BACs, we localizedRSPO1 on EAS 5q23,RSPO2 on EAS 12q13,RSPO3 on EAS 24q26, andRSPO4 on EAS 15p13. Moreover,RSPO2, RSPO3, andRSPO4 are the first genes mapped on donkey chromosomes 12, 24, and 15, respectively.