Genetics Vocabulary

Vocabulary: alleles –the different versions of a gene ex: P and p dominant traits – the expressed form of a trait ex: PP or Pp recessive traits – the trait not expressed, unless two are present ex: pp

Choosing your alleles: Purple flowers are dominant to white flowers. dominant traits –are expressed by writing the first letter of the trait as an uppercase letter ex: purple flower - P recessive traits –are expressed by writing the first letter of the dominant trait but as a lowercase letter ex: white flower - p

Selecting Your Alleles: Height: tall is dominant; short is recessive Eye color: brown is dominant; green is recessive Hair: curly is recessive; straight is dominant T t B b s S

More Vocabulary: homozygous – the two alleles of a particular gene are the same ex: PP or pp heterozygous – the two alleles of a particular gene are different ex: Pp genotype – the set of alleles (genes) for a trait ex: PP, Pp, pp phenotype - the physical appearance of a trait ex: purple flower, white flower

Homozygous or Heterozygous? Rr Tt ss Hetero PP tt Yy Homo Hetero Homo Homo Hetero

Genotype or Phenotype? PP Red hair Yellow seeds Rr Dimples Tt Yy ss Short PP Yellow seeds Dimples Yy Set of alleles P G G P G P G G P G

Practice: For each genotype below, indicate whether it is heterozygous (He), homozygous (HO D) or (HO r) Rr ______ HH _______ ii ______ Ww _______ For each genotype below determine what phenotypes would be possible. Curly hair is dominant to straight hair. Cc ________ CC _________ cc ________ He HO D HO r He Curly hair Curly hair Straight hair

Practice: For each phenotype below, list the genotypes. Remember to use the letter of the dominant trait. Green eyes are dominant to blue eyes. ______ green eyes _______ blue eyes ______ green eyes GG gg Gg

Other Terms You May See: Homozygous = Purebred MM mm Heterozygous = Hybrid Mm