1. Introduction to Genetics ANSWER KEY

2. Genetics #1 Study of how traits are passed on from one generation to another. #2 Traits from 1 st paragraph: –Hair color, eye color, –Flower color, –Hair type; long, short, curly, straight

3. One Trait = Two Genes 4) Blue Eyes –1 TRAIT –2 GENES (one from each parent) 5) Short plant with Red flowers –2 TRAITS –4 GENES 6) Blond, Curly, Blue Eyes –3 TRAITS –6 GENES

4. #7) Symbols represent traits: TraitAlleleSymbolAlleleSymbol Seed ShapeRoundRWrinkledr Flower ColorPurplePWhitep Pod ColorGreenGYellowg Pod ShapeInflatedIConstrictedi Flower position AxialATerminala

5. Genotype vs. Phenotype 8)Round seed shape: –Genotype = RR or Rr –Phenotype = round 9)Genotype of purple flower? –PP or Pp  Phenotype of short plant?  Short  Genotype of short plant? –tt

6. 10) Dominant vs. Recessive Dominant flower color? –Purple Dominant flower position? –Axial Recessive flower position? –terminal

7. 11) Dominant vs. recessive DOMINANT traits are symbolized with CAPITAL letters. (T, R, B) Recessive traits are symbolized with lower case letters (t, r, b). The letter selected for the symbol comes from the DOMINANT trait.

8. #12--Tall plant x Short plant Male TT X Female tt Offspring = Tt Tall

9. #13- Green pods (GG) x yellow pods (gg) GG X gg Offspring = Gg Green Pods

10. #14) Purple Flower x White flower PP X pp Offspring = Pp Purple Flowers

11. #15) Homozygous vs. Heterozygous BB –Homozygous Rr –Heterozygous rr –Homozygous Aa –Heterozygous YY –Homozygous

12. #17- Essential Vocab Genotype – the symbolized form; gene formula (ex: BB) Phenoypte – 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

13. #18- Vocab Check Notice blue eyes: –Phenotype Symbol for a trait: –Genotype Genotype for short pea plant: –Homozygous

14. #19- Application: Hair example Genotype of Curly parent: –CC Genotype of straight haired parent: –cc Offspring: –Genotype: Cc –Phenotype: curly haired Curly and straight always produce curly. Which trait is dominant? –Curly