genetic inheritance

• allele


  alternate version of gene
• chromosome


  long molecule of DNA found in nucleus
• gene


  section of DNA on chromosome that controls development of characteristic
• gamete

  sex cell
• dominant allele

  shown if two different alleles are present
• genotype


  what alleles you have
• heterozygous


  two different alleles for gene
• homozygous 


  two of same alleles for gene
• recessive allele

  shown when two copies of same allele present
• phenotype


  characteristics you have
• • some characteristics controlled by single gene
  • mouse fur colour
  • red-green colour blindness in humans
• • all genes have different forms called alleles
  • two alleles are in every gene
• • each body has 23 pairs of chromosomes
  • 22 pairs control characteristics
  • one pair of chromosomes determine sex
  • females - XX
  • males - XY