BIO 325 Lecture Notes - Lecture 13: Cystic Fibrosis, Wild Type, Genetic Linkage
Scaling Up Allele-Specific Oligo Hybridization
• Many genes have multiple polymorphisms that might cause disease
• Hundreds of mutations in CF gene that lead to the disease
• To test for all of the alleles, need to hybridize hundreds of allele specific oligos, one for
each allele; testing for known alleles
• Use microarrays
o Make allele specific oligos to every possible SNP that could occur in the gene
Alleles That Vary in Sequence Length
• Micro and minisatellites
• Small inserts and deletions
• PCR
• Gel
• Multiple alleles
DNA Fingerprinting
• Southern blot with micro or minisatellites
• Probes of ten selected that will hybridize to many sites in the genome
• Detect many polymorphisms at the same time
Lecture 18
Identify Genes That Underlie Disease
• Identify gene product (protein) directly
o Hemophilia
o Only possible in rare instances
• Identify gene by linkage to molecular markers
o Positional cloning
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Document Summary
Alleles that vary in sequence length: micro and minisatellites, small inserts and deletions, pcr, gel, multiple alleles. Dna fingerprinting: southern blot with micro or minisatellites, probes of ten selected that will hybridize to many sites in the genome, detect many polymorphisms at the same time. Identify gene product (protein) directly: hemophilia, only possible in rare instances. Identify gene by linkage to molecular markers: positional cloning, cystic fibrosis, more generally applicable. Hemophilia: hemophilia defining phenotype is uncontrolled bleeding, biochemically characterized blood clotting pathway, test purified blood clotting factors from wild type individuals and hemophiliacs, work backwards to get the gene, protein > dna > screen library. Identify which of the candidate genes is responsible for the phenotype. Low resolution mapping: lots of molecular markers, look for linkage between phenotype of interest and a molecular marker, distance between loci, less than 50 cm = loci is linkage, more than 50 cm = loci is not linkage.
