Alleles (Edexcel IGCSE Biology: Double Science)

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Alleles

  • A gene is a short length of DNA found on a chromosome that codes for a particular characteristic (expressed by the formation of different proteins)
  • Genes exist in alternative forms called alleles
  • Alleles are variations of the same gene
    • As we have two copies of each chromosome (one from each parent), we have two copies of each gene and therefore two alleles for each gene
    • One of the alleles is inherited from the mother and the other from the father
    • This means that the alleles do not code for the same thing
    • For example, an individual has two copies of the gene for eye colour but one allele could code for brown eyes and one allele could code for blue eyes
  • Having alleles give rise to differences in inherited characteristics and variation within species

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Lára

Author: Lára

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.