Artificial Selection

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Principles and uses

  • Selective breeding of organisms

  • Humans choosing desired phenotypes 

  • Only interbreed organisms with desired phenotypes

  • Therfore selecting the genotypes that contribute to the gene pool of next generation 

  • They continue to carry this process over many generations

  • Examples:

    • Cows- high milk yield, more docile

    • Sheep- finer quality wool

    • Dogs- better eyesight/hearing for hunting

    • Cats- more docile, shorter claws

Inbreeding depression and hybrid vigour

  • Genetic diversity is reduced in gene pool 

  • Harmful alleles become more frequent

  • Reduces chance of survival if environment were to change (e.g. new pathogens introduced)

  • Inbreeding depression can occur (closely related individuals inbred)

  • To overcome this, we need to outcross individuals with different varieties 

  • Increasing heterozygotes is called “hybrid vigour

  • Need to

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