Download Genetic Vocabulary - Renton School District

Essential Vocab
• Genotype – the symbolized form; gene forumula (ex: BB)
• Phenotype – physical appearance/description (ex: brown)
• Homozygous – 2 genes that are the same (ex: BB or bb) ; Pure
Bred
• Heterozygous – 2 genes that are different (ex: Bb) ; Hybrid
• Dominant – the stronger gene; appears in the phenotype if
present
• Recessive – the weaker gene; appears in the phenotype only
when homozygous
Genetic Vocabulary
• Phenotype: the actual appearance of trait as it is expressed—what you see
• Example: blue eyes
• Genotype: term given to the genes on the chromosomes, which genes are present on
chromosomes
• Example: Pp or Xx
• Dominance: term given to gene that is expressed phenotypically, no matter what the genotypic
make-up; if this gene is present the trait will be seen
• Recessive: term given to gene that is only expressed phenotypically if the offspring carries both
genes—in other words, received a recessive gene from both parents
• Homozygous: When genes are the same, both dominant or both recessive; will be visibly seen as
either dominant or recessive trait
• Heterozygous: When genes are different, offspring has one dominant and one recessive gene;
phenotypically, the offspring will express (show) the dominant gene
• Incomplete Dominance: A mixture of genetic material; EX: Red flowers crossed with White
flowers make pink flowers