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Positional cloning: Getting there by linkage PowerPoint Presentation
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Positional cloning: Getting there by linkage

Positional cloning: Getting there by linkage

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Positional cloning: Getting there by linkage

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  1. Positional cloning: Getting there by linkage • In most instances, human disease genes cannot be localized by physical landmarks, e.g., deletions or translocations • Genetic linkage analysis is thus essential and requires: • large number of families • marker polymorphisms in the families • informative meioses

  2. HD: Proof of principle and 10 long years • The principle was to find a closely linked marker • G8 marker found after only 12 attempts! (1983) • large families were a key resource • mapping to Chrm. 4 by somatic cell hybrids • Finally: gene discovery by transcript analysis • Confirmation by mutation analysis: a trinucleotide repeat (1993)