Genetics

• Heredity

  The passing of traits from parent to offspring
• Allele

  A specific form of a gene, there are two of them
• Trait

  Any characteristic that can be passed down from parent to offspring
• Dominant trait


  A trait that is always expressed over the recessive and shown with a capital letter
• Recessive trait


  A trait that is only expressed when both alleles are recessive, shown with lowercase letters
• Genotype


  The written expression of a trait, it is a code shown with letters
• Phenotype


  The physical characteristics that you see
• Homozygous

  Same size letters, either both dominant or both recessive. Also called purebred.
• Heterozygous


  Different size letters, one dominant and one recessive
• Gene

  A small segment of DNA that codes for a trait
• One gene can code for one protein
• The DNA is the same in every type of cell or organ
• How sexual reproduction can lead to genetic variation in a population?

  1. When two different parents reproduce, different children will be born

  2. Both parents over generations of variation in individuals lead to variation of a population
• Mutations

  • Differences in DNA
  • Any change to the DNA sequence in a gene or chromosome
  • Can be beneficial or harmful
  • Can occur randomly or from parents
• A punnet square can be used to predict the genotype and phenotype of offspring.