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Biology LibreTexts

24: Genetic Linkage

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    • 24.1: Linkage
      Mendel’s Second Law does not apply to every pair of genes that could be studied. In fact, we now know that alleles of loci that are located close together on the same chromosome tend to be inherited together. This phenomenon is called linkage, and is a major exception to Mendel’s Second Law of Independent Assortment. Researchers use linkage to determine the location of genes along chromosomes in a process called genetic mapping and is important to natural processes of heredity and evolution.
    • 24.2: Recombination
      In heredity, recombination is any process that results in gametes with combinations of alleles that were not present in the gametes of a previous generation. Interchromosomal recombination occurs either through independent assortment of alleles whose loci are on different chromosomes. Intrachromosomal recombination occurs through crossovers between loci on the same chromosomes . In both cases, recombination is a process that occurs during meiosis (mitotic recombination is relatively rare).
    • 24.3: Linkage Reduces Recombination Frequency
    • 24.4: Crossovers Allow Recombination of Linked Loci
    • 24.5: Inferring Recombination From Genetic Data
    • 24.6: Genetic Mapping
      Because the frequency of recombination between two loci (up to 50%) is roughly proportional to the chromosomal distance between them, we can use recombination frequencies to produce genetic maps of all the loci along a chromosome and ultimately in the whole genome.