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Published byCorey Ada Todd Modified over 8 years ago
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Mendel’s Punnett Squares
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Genes and Alleles Gene: Place on chromosome and determines certain trait Allele: variation of that trait Ex: Gene: Eye color Located on 5 th gene from the top Alleles: Brown, Blue, Green, Gray
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Mendelian Traits Each trait 1 gene with 2 variations or 2 alleles For each allele, 1 is Dominant 1 is Recessive Dominant has a capital letter while recessive has lower case letter A genotype= is the actual allele combination (Aa, AA, aa) A phenotype= is what trait that expresses (Tall or Short)
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Types of genotypes and phenotypes If an individual is purebred=homozygous If an individual is homozygous dominant= AA If an individual is homozygous recessive= aa If an individual is heterozygous= Aa Phenotypes – Homo Dom. and Heterozygous expresses dom allele – Homo Rec. expresses recessive allele
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Genotypes and Phenotypes Example Eye color – The allele for blue eye color is ‘b’ – The allele for brown eye color is ‘B’ 1.What is the phenotype of picture A? What is it’s genotype? 2.What is the phenetype of picture B? What is its genotype? A B
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Getting a phenotype from a Genotype Eye color – The allele for blue eye color is ‘b’ – The allele for brown eye color is ‘B’ 1.What is phenotype of Bb? 2.What is the phenotype of bb? 3.What is the phenotype of BB?
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Predicting ratios This is where you are given two individuals an pretending they are making a child, but before they make the child they want to the probability of getting a particular trait Scenario Blue eyed and Brown eyes person with genotypes of ‘bb’ and ‘BB’ What are the ratios of the genotypes: BB- Bb- bb- What are the ratios of phenotypes: Blue eyes- Brown eyes-
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3 Possible Monohybrid Crosses Type 1 AA x aa Phenotype ratios: Genotype ratios
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3 Possible Monohybrid Crosses Type 2 AA x Aa Phenotype ratios: Genotype ratios
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3 Possible Monohybrid Crosses Type 3 Aa x Aa Phenotype ratios: Genotype ratios
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3 Possible Monohybrid Crosses Type 4 Aa x aa Phenotype ratios: Genotype ratios
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