( ould have taken many monthswere com...)Map and Link Human Genetic Disorders with SSLP Analysis

Linkage Studies Analyzed

We used Stratagenes CastAway system to analyze linkage studies of many families with inherited disorders. Stickler syndrome is one of the milder phenotypes that results from mutations in the gene encoding type II collagen, COL2A1.^4,5 Genetic heterogeneity has been demonstrated for Stickler syndrome, with mutations in two genes that encode type XI collagen, COL11A1 and COL11A2, and in at least one additional unidentified gene, resulting in Stickler syndrome.^6,7 To determine if the phenotype in a family with Stickler syndrome is linked to the COL11A1 or COL11A2 locus (COL2A1 was previously excluded as the Stickler syndrome gene in this family⁷), polymorphic markers were analyzed by PCR amplification of the genomic DNA. A (CA)n repeat microsatellite marker, D1S206, was analyzed as one of a number of polymorphic markers in chromosome 1p21. The markers were analyzed to generate haplotypes across the region of chromosome 1 containing COL11A1. Analysis of polymorphic markers within the COL11A1 gene and a-amylase (AMY2B) gene completed the haplotypes. Analysis of these haplotypes excluded COL11A1 as a candidate for Stickler syndrome in this pedigree. Haplotype analysis, using markers in chromosome 6p21.3, also excluded COL11A2 as a candidate for Stickler syndrome in this pedigree.

In a genotyping experiment using the marker D1S206, PCR products were analyzed on a denaturing polyacrylamide gel to resolve allelic differences that were greater than 2 bp (Figure 1, Panel A). Five alleles, labeled A through E (Figure 1, Panel A) were identified for this marker, with each allele differing by at least 2 bp, representing multiples of (CA) dinucleotides. Each allele
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