DIHYBRID PUNNETT SQUARES We have been studying Monohybrid
DIHYBRID PUNNETT SQUARES
We have been studying Monohybrid Punnett Squres ■ Mono-Means one ■ Monohybrid Punnett Square-We are looking at a cross (or mating) where only one trait is being studied ■ Example: Short or tall Yellow or Green Long or stubby
Dihybrid Punnett Squares ■ A cross (or mating) between two organisms where two genes are studied ■ The genes are located on separate chromosomes, so the traits themselves are unrelated. ■ Example – Long hair or short hair and black color or white – Tall or Short and Yellow or Green
To introduce you to Dihybrid Punnett Squares were are going to look at Guinea Pigs And the following Traits ■ BB-Black Hair Color ■ Bb-White Hair Color ■ LL- Short Hair ■ Ll-long Hair
In a Dihybrid Cross we have to do distribution of properties to determine the genotype of the parents. We call it the Gamete combination ■ We will be using the FOIL method to distribute our Gametes FOIL First Outer Inner Last
Let’s look at FOIL Black Guinea Pig with Short Hair White Guinea Pig with Long Hair Outer First B B LInner. L Last Outer First b b Inner ll Last
Now you Practice Foil Outer First B b LInner l Last BL Bl b. L bl Outer First B b l. Inner l Last Bl Bl bl bl
Foil BL Bl b. L bl Now let’s do the Punnett Square Keep the letter combinations together. This makes it easier to read the traits BL Bl b. L bl BBLl Bb. LL Bb. Ll BBLl Bb. LL BBll Bb. Ll Bbll Bb. Ll bb. LL bb. Ll Bbll bb. Ll bbll
9: 16 3: 16 1: 16
Now it is your turn to practice ■ We will be walking around to help. ■ Finish the Guinea Pig Worksheet ■ Then start on the Sponge. Bob Dihybrid Worksheet
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