Alleles

• Chromosomes


  Come from each of your parents
• Genes


  Sections of DNA on a chromosome
• Versions of genes

  • Alleles
• Earwax gene

  Has 2 alleles: one for wet earwax(E) and the other for dry earwax(e)
• Genotype

  The alleles present
• Homozygous


  Two copies of the same allele
• Homozygous genotype


  • ee
• Phenotype

  The characteristics caused by a person's alleles
• Heterozygous


  Two different alleles
• Heterozygous genotype


  • Ee
• Dominant allele


  Shows in the phenotype even if there is only one copy present
• Recessive allele


  Only shows if two copies are present