Learn More (nonallelic homologous recombination)

nonallelic homologous recombination

Illustration adapted from Nussbaum RL, McInnes RR, Willard HF, eds: Thompson & Thompson Genetics in Medicine, 6 ed. Genetic variation in individuals: mutation and polymorphism, Fig 6-2A, p 84. Copyright 2001, with permission from Elsevier.

Situations more susceptible to unequal crossing over

  • Members of multigene "families" in which genes share significant homology with one another (e.g., alpha globin gene cluster; red and green visual pigment gene cluster)
  • A gene and pseudogene in tandem on a chromosome (e.g., CYP21 and its pseudogene CYP21P, GAB and its pseudogene GABP)
  • Similar sequences along the same strand of DNA predisposing to inversions or deletions (e.g., F8 inversion; contiguous gene deletions, such as 22q11.2 deletion)
  • Homologous noncoding sequences (e.g., Alu family of repeated DNA sequences interspersed throughout the genome)

Revised: 11-16-16

Related terms: deletion; duplication; gene conversion; recombination

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