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Published byEvelyn Andrews Modified over 9 years ago
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Do Now 1.Identify the heterozygous and homozygous alleles from below. 1.Aa BB Bb Tt tt Kk Ll GG Oo ZZ
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GU plays tonight at 11 pm on ESPNU Homework tonight Quiz on Friday Progress Reports on Monday Announcements
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Bean Genes Lab Punnett Squares Agenda
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Please be careful not to make a mess! Bean Gene Lab
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Please be careful not to make a mess! Punnett Squares
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Punnett Square Why? Way of predicting the likelihood (probability) of offspring carrying certain genetic traits!
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What do we need to know? 1. Genotype of parents 2. Which allele is dominant
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Purebred = Homozygous Purebred: Both alleles are for the same trait Example: FF
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Hybrid = Heterozygous Hybrid = The alleles are mixed; they are for different traits Example: Ff
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Quick Check: Homozygous = stand up, Heterozygous = sit down BB Homozygous Bb Heterozygous bb Homozygous bB Heterozygous
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Remember, capital letters are dominant!
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Let’s try another Punnett Square! Hair Color in Humans B = brown = dominant b = blonde = recessive Let’s say Kevin Federline and Britney Spears are having a baby…
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KFed is heterozygous for brown hair, so…. His genotype is Bb B b And Britney is homogenous for blonde hair, so…. Her genotype is bb bb Bb bb
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B b bb Bb bb GenotypeRatioPercentagePhenotypeRatioPercentage Bb2/4 50% Brown Hair2/450% bbBlonde Hair2/4 50% The likelihood that an offspring will have Brown Hair is ______________. The probability that an offspring will have Blonde Hair is ____________.
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***Important*** Probability is the likelihood something will happen, or the chance that something will happen. If there is a 25% chance that your kids will have blue eyes, it does not mean that if you have 4 kids one of them is definitely going to have blue eyes!
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Widow’s Peak A recessive gene W = Normal Hairline w = Widow’s Peak
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Let’s say you have two parents who are heterozygous for the gene 1. What are the chances that their offspring will have a widow’s peak? 2. What are the chances that their offspring will not have a widow’s peak but will carry an allele for a widow’s peak? 3. What are the chances that their offspring will not have a widow’s peak and will not carry a gene for a widow’s peak? What are their genotypes? Ww and Ww
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Let’s see what happens if the parents have the following genotypes: Ww and ww 1. What are the chances that their offspring will have a widow’s peak? 2. What are the chances that their offspring will not have a widow’s peak but will carry an allele for a widow’s peak? 3. What are the chances that their offspring will not have a widow’s peak and will not carry a gene for a widow’s peak?
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