Do now activity In pea plants, yellow seed color (Y) is dominant over green seed color (y). Complete the cross between a plant that is heterozygous for yellow seeds and a plant that is homozygous recessive.

Section 4-3: Punnet Squares Essential Question: How can a punnet square be used to predict the probability of offspring genotypes and phenotypes based on the parents genotype? Learning Target Use a punnett square to predict the probability of offspring genotypes and phenotypes based on the parents genotype. Section 4-3: Punnet Squares

announcements Biology Tutoring schedule W&F @ 7:00AM Section 4 Test Scheduled for Friday: 11/17/17 Section 4 Lab TBA Class website will be updated today

announcements Available Extra Credit: 3 Tissue Boxes = 1 class pass Color Printer Paper = 1 class pass Plastic Pencil Box = 1 class pass

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Probability: the likelihood that an event will occur. overview cyclins Probability: the likelihood that an event will occur.

When you flip a coin, what is the probability that you will get Tails? overview When you flip a coin, what is the probability that you will get Tails? cyclins

The probability of a particular event occurring from a coin toss is overview Example: Coin Toss The probability of a particular event occurring from a coin toss is ½ or 50% cyclins

overview Example: Coin Toss Possible events: Heads = ½ or 50% probability Tails = ½ or 50% probability cyclins

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Traits Based on genetic information, we can use a Punnet Square to determine the probable traits of our children. cyclins

Traits are controlled by genes cyclins

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Punnet squares Steps Define your letters Set up your cross-breed Draw your Punnet Square Law of Segregation Solve the Punnet Square Calculate probabilities cyclins

Mono-Hybrids: crosses between parents for a ______ trait. Punnet squares Mono-Hybrids: crosses between parents for a ______ trait. Examples: Dimples, Cleft chin, Freckles, Widow peak single single

Punnet squares Di-Hybrids: crosses between parents for two ________ traits. Examples: Freckles & Cleft chin Dimples & Widow peak different different

Punnet squares Di-Hybrid = combining 2 different traits Ex. Freckles x Dimples

Practice question In humans, tongue rolling is dominant over non-tongue rolling. Use a Punnett square to predict the probability of having a non- tongue rolling baby for a cross between a person heterozygous for tongue rolling and a person who is homozygous for non-tongue rolling. cyclins

Practice question Heterozygous for tongue rolling And T t homozygous for non-tongue rolling. T t t T t t t cyclins T t t t

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Alleles separate during ______ formation Law of segregation Alleles separate during ______ formation gamete gamete

Law of segregation Dominant Allele The trait is always expressed Shown by a capital letter cyclins

Law of segregation Recessive Allele Trait is expressed when a dominant allele is not there Shown by lowercase letter cyclins

Gametes Segregation Parent Generation D d D d Baby Generation DD Dd Dd dd Results: DD = Dimples Dd = Dimples dd = no dimples 75% Dimples, 25% No Dimples

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Practice Question! In humans, straight thumb (S) is dominant over hitch-hikers thumb ( s ). Use a Punnett square to predict the probability of having a baby with hitch-hiker thumb for two people heterozygous for straight thumb. cyclins

Practice Question! And S s S s S S S s S s s s Heterozygous for straight thumb And Heterozygous for straight thumb. S s S s S S S s cyclins S s s s

Practice Question! T t T t T t T t The allele for tall plant (T) is dominant over the allele for short plant (t). A homozygous tall plant is bred with a homozygous short plant. T t T t cyclins T t T t

How is it possible to have 100% TALL Practice Question! How is it possible to have 100% TALL pea plant offspring when the genes were 50% Tall (mom) and 50% Short (dad)? T t T t T t T t

Do now activity Dimples (D) is dominant over no dimples (d). A woman heterozygous for dimples has a child with a man heterozygous for dimples. *Use a punnet square to determine the probability of the couple having a child without dimples.