ALLELES

• ALLELES:

  • VERSIONS of a GENE
• GENE:

  • Some CHARACTERISTICS are caused by a single GENES e.g. RED / GREEN colour BLINDNESS, mice fur COLOUR
  • Most CHARACTERISTICS are caused by MULTIPLE genes INTERACTING e.g. HEIGHT
• GENOTYPE:

  • ALLELES that are PRESENT
• PHENOTYPE:

  • PHYSICAL characteristics
  • Caused by ALLELES
• HOMOZYGOUS:

  • 2 copies of the SAME ALLELE
  • "HOMO" means the SAME
• HETEROZYGOUS:

  • 2 copies of DIFFERENT ALLELES
• DOMINANT ALLELE:

  • Shows in PHENOTYPE even if 1 is present
• RECESSIVE ALLELE:

  • Only shows in PHENOTYPE if 2 copies are present (no DOMINANT allele)