Genotype And Phenotype

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Genotype and Phenotype Target: I will be able to use the principles of dominance to identify the phenotype given a genotype. Homozygous: When an organism has two of the same alleles for a certain trait. For example TT, tt. Pg. 19

Heterozygous: When an organism has two different alleles for a certain trait. For example Tt. Pg. 23

Genotype: Combinations of gene alleles in an individual. TT, Tt, or tt. Phenotype: Physical expression of genes that determine an individual’s appearance. Tall or Short.

Two organisms can have the same phenotype but different genotypes. For example: Both individuals can have Brown eyes, but one can be homozygous (BB) and one can be heterozygous (Bb). Lets practice!

RR Right Handed Rr Right Handed rr Left Handed Hh Hairy Knuckles Trait Genotype Phenotype Handedness Right = Dominant Left = Recessive   Knuckle Hair Hairy = Dominant No Hair = Recessive Cheeks Dimples = Dominant No Dimples= Recessive RR Right Handed Rr Right Handed rr Left Handed Hh Hairy Knuckles Not Hairy Knuckles hh Hairy Knuckles HH dd No Dimples DD Dimples Dd Dimples

BBWw aabb bbWW Bushy Eyebrows, Ability to winks both eyes Trait Eyebrows (B/b) Bushy = Dominant Fine = Recessive Eye Shape (A/a) Almond = Dominant Round= Recessive Eye Winking (W/w) Both eyes = Dominant 1 eye = Recessive Genotype Phenotype   Bushy Eyebrows, Ability to winks both eyes BBWw   Round eyes, Only winks 1 eye aabb   Fine eyebrows, Ability to winks both eyes bbWW

Summary: Examples of Inheritable Traits: Hairline Eye Color Tongue Rolling Earlobes Hitchhiker Thumbs Thumb Crossing Bent Pinky Finger Summary:

Studying my Genes 1. With a partner go through the Studying my Genes Worksheet, helping each other decide which alleles they have and what the genotypes and phenotypes are. Remember: If you have the dominant trait, only write 1 capital letter in the genotype column since we don’t know if you are homozygous or heterozygous. If you have the recessive trait, you should write 2 lowercase letters 2. Count up their amount of dominant/recessive alleles you have and answer the first question at the bottom of the page. 3. Then count up how many students in the class have each trait and use the class data, answer the second question. 4. Finish the worksheet by analyzing what it truly means to be dominant (question #3) Pg. 18