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#heterozygote advantage

2 public questions tagged with this topic.

ORIGIN OF LIFE

Balancing selection tends to:

Maintain variation reflects key principle in quiz on pyqs-evo theories + genetic drift, where evolutionary mechanisms shape genetic variation and adaptation. In this context, Maintain variation aligns with experimental and theoretical evidence from population genetics, behavioral ecology and molecular phylogeny. Textbooks like Campbell Biology, Futuyma Evolution and Hartl Principles illustrate supporting data. Understanding why Maintain variation fits helps integrate natural selection, environment.

Ref: Hartl & Clark, Principles of Population Genetics, Drift and Effective Size.

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Population Genetics

Heterozygote advantage is an example of

Balancing selection maintains multiple alleles stably in population rather than favoring single variant toward fixation and loss. Heterozygote advantage, also called overdominance, is a classic form of balancing selection where heterozygous genotype fitness exceeds both homozygous genotypes, preventing elimination of either allele. This opposes directional and disruptive selection that reduce variation over time. Classic examples include sickle cell polymorphism and MHC diversity maintained by pathogen pressure. By selecting against both homozygote classes, heterozygote superiority preserves stable polymorphism, categorizing it under balancing selection mechanisms counteracting genetic drift.

Ref: Hartl & Ruvolo, Genetics, 6th ed., Chapter 21: Balanced Polymorphism and Overdominance Theory

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