Key Words

• Homozygous


  2 identical alleles for a particular gene (e.g. AA or aa).
• Heterozygous


  2 different alleles for a particular gene - one dominant and one recessive.
• Genotype


  The genetic make up of an organism (i.e. the two alleles it has for a particular gene Bb)
• Phenotype


  The physical appearance of an organism as a result of its genotype.
• Gene


  A short section of DNA that codes for a protein which determines your characteristics.
• Allele


  A different form of gene, either recessive or dominant.
• F1


  First family cross
• F2


  Second family cross.
• 'Selfing'


  Two offspring from the same cross breed together.
• Dominant


  An allele which is always expressed if present in the genotype.
• Recessive


  An allele which is only expressed if there are no dominant alleles present in the genotype.
• Genetic modification


  When a desired gene has been removed from one organism's chromosome and inserted into the chromosome of another organism.