An exchange occurs between identical chromatids. B B B B (a) Sister chromatid exchange A Two with Meiosis is completed to yield 4 haploid cells. parental A crossover occurs between homologous chromatids. genotype B B в ь в by Two with recombinant genotype ь (b) Recombination between homologous chromosomes during melosis FIGURE 20.1 Two types of homologous recombination in eukaryotes. (a) Homologous recombination between sister chromatids. (b) Homologous recombination between homologous chromatids. This second form of homologous recombination may lead to a new combination of alleles, which is called a recombinant (or nonparental) genotype. Genes-Traits Homologous recombination is particularly important when we consider the relationships between multiple genes and multiple traits. For example, if the X chromosome in a female fruit fly carried alleles for red eyes and gray body and its homolog carried alleles for white eyes and yellow body, homologous recombination could produce recombinant chromosomes that carry alleles for red eyes and yellow body, or alleles for white eyes and gray body. Therefore, new combinations of two or more alleles can arise when homologous recombination takes place.

An exchange occurs between identical chromatids. B B B B (a) Sister chromatid exchange A Two with Meiosis is completed to yield 4 haploid cells. parental A crossover occurs between homologous chromatids. genotype B B в ь в by Two with recombinant genotype ь (b) Recombination between homologous chromosomes during melosis FIGURE 20.1 Two types of homologous recombination in eukaryotes. (a) Homologous recombination between sister chromatids. (b) Homologous recombination between homologous chromatids. This second form of homologous recombination may lead to a new combination of alleles, which is called a recombinant (or nonparental) genotype. Genes-Traits Homologous recombination is particularly important when we consider the relationships between multiple genes and multiple traits. For example, if the X chromosome in a female fruit fly carried alleles for red eyes and gray body and its homolog carried alleles for white eyes and yellow body, homologous recombination could produce recombinant chromosomes that carry alleles for red eyes and yellow body, or alleles for white eyes and gray body. Therefore, new combinations of two or more alleles can arise when homologous recombination takes place.

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter6: Cytogenetics: Karyotypes And Chromosome Aberrations

Section: Chapter Questions

Problem 3QP: A colleague e-mails you saying that she has identified an interesting chromosome variation at 21q13....

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