Abstract: The present invention relates to the field of sheep genetics. Specifically, it relates to materials and methods used to detect a recessive gene causative for hereditary chondroplasia or “Spider Lamb Syndrome”. Disclosed are genetic markers for Spider Lamb Syndrome and methods for screening sheep to differentiate those that possess no, one, or two copies of the Spider lamb Syndrome defective gene. In addition, methods are described for identifying other markers associated with Spider Lamb Syndrome. The markers are based upon the presence or absence of certain polymorphisms in the ovine fibroblast growth factor receptor 3 gene. Preferably, the polymorphisms are detected as polymerase chain reaction-restriction fragment length polymorphisms or single strand conformational polymorphisms.