Plant & Animal Genome VI Conference

P346

POLYMORPHIC DNA MARKERS

1. DPN U-156, University of Connecticut, Storrs, CT 06269-4156
2. Mail stop 253, Perkin Elmer Corp., 50 Danbury Rd., Wilton, CT 06470

Success in aquaculture requires knowledge of the gene(s) which underlying fitness traits and an ability to manipulate those genes. One of the first steps in isolation and characterization of such genes is the generation of a chromosomal map. Argopectin irradians has attracted a great deal of attention lately as a potential aquaculture organism. Argopectin irradians has been shown to possess 32 chromosomes but chromosomal organization has not been characterized. We have characterized several hundred ESTs from a directionally cloned cDNA library constructed with mRNA isolated form Argopectin irradians adductor muscle. We have also isolated several polymorphic DNA markers from RAPD screens of the Argopectin irradians genome, e.g., (TCCTGTCAAAC(TAACC)₂)₈. To construct a partial chromosomal map, we constructed a genomic library in a PWE15 vector with an average insert size of 40kb. To characterize the presence of an EST or polymorphic DNA marker within a genomic library clone, radiolabeled clones were hybridized to a panel of ESTs and polymorphic markers on a solid support. After identification of the presence of an EST(s) or polymorphic marker(s) within a genomic clone, PCR primers, specific to the EST or polymorphic markers, were used to map the location of the markers within the clone. To map the genomic clone to chromosomal location, unfertilized eggs were used to make chromosomal smears and then hybridized with fluorescently tagged specific fragments of the genomic clone (i.e., FISH). We have begun to use this partial map to characterize the genetic differences between fast and slow growing Argopectin irradians aquaculture strains.