02 Gene Mapping

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Genetic Recombination

• The law of segregation describes the phenomenon in which gametogenesis results in the separation of paired chromosomes so that the offspring inherit only half of each parent's genetic composition.

• 50% chance gametes will have parental version of genes
• 50% chance of either having FM or fm

• 50% chance for recombinant

• use frequency of recombination of genes to determine how far each gene is away from each other
• recombination of AB 16%
• AB farther apart, higher frequency of recombination
• AC closer, smaller frequency

Linkage Disequilibrium

• even with large family, may never see recombination event

• expected frequency of mixture of allele
• if expected similar to reality = linkage equilibrium
• not similar to Hardy Weinberg law (same gene, different alleles)

• closer together = greater linkage disequilibrium
• use linkage disequilibrium to study genes close together that can't study with family

• at first, disequilibrium highest because closest together
• with later generations, farther apart, more in equilibrium