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Biology LibreTexts

6.S: Genetic Analysis of Multiple Genes (Summary)

  • Page ID
    4090
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    • The alleles of different loci are inherited independently of each other, unless they are genetically linked.
    • The expected phenotypic ratio of a dihybrid cross is 9:3:3:1, except in cases of linkage or gene interactions that modify this ratio.
    • Modified ratios from 9:3:3:1 are seen in the case of recessive and dominant epistasis, duplicate genes, and complementary gene action.  This usually indicates that the two genes interact within the same biological pathway.

    Key Terms

    Mendel’s Second Law

    Dihybrid

    9:3:3:19:3:4

    12:3:1

    independent assortment

    linkage

    recessive epistasis

    dominant epistasis

    complementary action

    redundancy

    duplicate gene action

    Orange, long, dilute, White masking, piebald spotting, calico

     

     

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