pedigree chart

• Recessive traits are only expressed when both copies of the gene are recessive.
• A dominant trait will always be expressed, even if only one copy of the gene is present.
• Dominant alleles mask or hide recessive alleles, resulting in dominant phenotypes.
• A pedigree chart uses certain symbols and track a certain trait (eg. gender, etc) generations back.

  
• Pedigree Chart example: