Organization and Southern blot analysis of the Atlantic salmon zonadhesin-like gene ( zlg ). A) Domain structure, probe locations, and EST coverage of the Atlantic salmon Zlg. The three VWD domains, the two MAM domains and the mucin domain are shown. The signal peptide (SP) and poly (A) tail are also indicated. Probe 1 included 177 nucleotides of the 3'-UTR and 206 nucleotides of VWD3 in the coding region. Probe 2 included 233 nucleotides of the 3'-end of VWD1. The 4388 bp EST covers the full length of the cDNA sequence except for the 5'-UTR which is estimated to be approximately 200 bp by comparison to Northern blot data. B) Southern blot analysis of Atlantic salmon and rainbow trout genomic DNA. Gene copy number was assessed by genomic hybridization. Twenty micrograms of Atlantic salmon (A.S.) and rainbow trout (R.T.) genomic DNA were digested with four enzymes, Eco R I, Hind III, Bam H I and Bgl II and hybridized with radiolabeled probe 1 representing the 3'-end of the zlg mRNA.