Frayer Model
Vocabulary Review
Genotype
• Definition: Set of alleles that an individual has
for a character
• Characteristics: pair of alleles, written as two
letters, determines genotype, etc.
• Examples: PP, Ee, tt
• Non-examples: blue eyes, freckles, tall plant
Phenotype
• Definition: trait that results from an
individual’s alleles
• Characteristics: physical appearance/trait,
visible, determined by genotype
• Examples: blue eyes, freckles, tall plant
• Non-examples: PP, Ee, tt
Dominant
• Definition: expressed when allele is present in
a genotype/individual
• Characteristics: “wins” over other alleles,
overshadows recessive allele, expressed,
capital letter
• Examples: brown eyes, freckles, dimples
• Non-examples: blue eyes, no freckles, no
dimples
Recessive
• Definition: only expressed when dominant
allele is not present
• Characteristics: written as lower case letter,
usually overshadowed, only expressed in
homozygous condition
• Examples: blue eyes, no freckles, no dimples
• Non-examples: brown eyes, freckles, dimples
Homozygous
• Definition: having two identical alleles for a
characteristic
• Characteristics: SAME, two dominant or two
recessive
• Examples: PP, tt
• Non-examples: Bb
Heterozygous
• Definition: having two different alleles for a
characteristic
• Characteristics: DIFFERENT, one dominant &
one recessive
• Examples: Bb
• Non-examples: PP, tt