Linkage and physical mapping of prolactin to porcine chromosome 7

Comparative mapping studies between human and pig have shown that there is conserved synteny between human chromosome 6 and pig chromosomes 1 and 7, but some gene locations are not well established. Prolactin (PRL), an anterior pituitary hormone, has been mapped to human chromosome 6, and has tentatively mapped to pig chromosome 7 using Southern-RFLP analysis with a limited number of meioses. To confirm the assignment of prolactin to porcine chromosome 7 by physical and linkage analysis, pig cDNA and human genomic DNA sequences were used to design pig-specific PCR primers. The primers amplified a fragment of approximately 2.8 kb. Two polymorphic restriction sites were identified within this fragment with the restriction endonuclease BstUI. Prolactin was significantly linked to six markers on the published PiGMaP map of pig chromosome 7. Prolactin was physically mapped using a pig x rodent somatic cell hybrid panel. An analysis of these data placed PRL on pig 7p1.1-p1.2 with 100% concordance and was in complete agreement with the linkage data. Both mapping techniques placed PRL in a conserved order with the loci in the syntenic region of human chromosome 6.