[1] CNR, ISPAAM, Lab Anim Cytogenet & Gene Mapping, I-80125 Naples, Italy
[2] Univ Pavia, Fac Sci, Dept Genet & Microbiol, I-27100 Pavia, Italy
[3] Univ Naples, Fac Vet Med, Dept Pathol & Anim Hlth, I-80138 Naples, Italy
[4] Roslin Inst, Roslin EH25 9PS, Midlothian, Scotland
[5] INRA, Dept Anim Genet, Lab Biochem Genet & Cytogenet, Jouy En Josas, France