Punnett Squares Write on the right side

* Remember alleles can be dominant or recessive.* Different versions of genes are called alleles * Remember alleles can be dominant or recessive.*

Punnett Square A graphic used to predict the possible genotypes of offspring. Think about it: Each parent has 2 alleles for each gene. Their offspring receive one of those alleles from each parent (so the offspring also have 2) Punnett squares show us a possible combination the offspring will receive

Getting a Better Understanding Punnett squares Getting a Better Understanding The letters on top show one parent’s alleles for that trait The letters on the side show the other parent’s alleles for that trait Each box shows a possible combination the offspring will have

Making Predictions Punnett squares help us find probabilities of certain genotypes. (a probability is the chance of getting a certain outcome in relation to the total number of outcomes) We usually use ratios or percentages to represent probabilities. percentage 25% 50% 1 out of 4 1:4 2 out of 4 2:4 ratio 50% 2 out of 4 2:4 25% 1 out of 4 1:4

Now Let’s practice Fill in each box in the Punnett squares with the combination of alleles that the offspring would have. A A T t a T t

Now Let’s practice Now find the probabilities of each outcome and write them in the blanks below. A A T t Aa Aa TT Tt a T t Aa Aa tt Tt AA_____ Aa_____ aa_____ TT_____ Tt_____ tt_____

Reflection Complete the “Do the Math: You try it” questions on page 449 in your textbook. Cut out that section and glue/tape/staple it on the left side of your journal next to your Punnett Square notes