Genetics Notes!

True-Breeding = Homozygous – having 2 alleles for a given trait that are the same (EX. Both parents gave you blue eyes); written as TT or tt (same size) Hybrid = Heterozygous – Having 2 different alleles for a given trait (EX. Mom gave you blue eyes and dad gave you brown eyes); written as Tt Dominant – version of an allele that always shows if present regardless of what the other allele is. Symbolized by CAPITALS (T for tall) Recessive – version of an allele that ONLY shows if there is no dominant allele present (ie. When there are 2 recessive alleles). Symbolized by lower case (t for short)

5) Genotype – 1) genetic make-up 2) which alleles are present in the DNA 3 ways to describe: *Homozygous Dominant TT *Heterozygous Tt (dominant shows *Homozygous Recessive tt 6) Phenotype – physical characteristics – “We can see or detect” (EX. – tall, short, blue eyes, able to taste PTC)

Mothers Genotype - one spot = one allele Punnett Squares Mothers Genotype - one spot = one allele Inside boxes represent Possible outcomes of genetic cases. *Using numbers 1&2 for mother’s genotype and 3&4 for fathers Father's alleles

How to do Punnett Squares 2) Place each letter of mother's genotype over a box 1) Draw box 1 2

1 2 1 2 1 2 3 4 3 4 1 2 4) Copy MG into 3) Place each letter of boxes below each allele 3) Place each letter of father's genotype next to box 1 2 1 2 1 2 3 4 3 4 1 2

5) Copy FG into boxes beside each allele 1 2 1 3 2 3 1 4 2 4 3 4

If there are multiple letters, put in alphabetical order. AaBBcc or XY Show Dominant (T) before Recessive – Aa (never aA)