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DIHYBRID CROSS REVIEW
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Unattached earlobes (E) is dominant to attached earlobes (e)
Unattached earlobes (E) is dominant to attached earlobes (e). Widow’s peak (H) is dominant to a straight hairline (h). If a male who is heterozygous for both traits marries a female who is homozygous recessive for earlobes and homozygous dominant for hairline, answer the questions. Parent Genotypes: EeHh x eeHH EH Eh eH eh What percent of F1 offspring have unattached earlobes and widow’s peak? eH EeHH EeHh eeHH eeHh 50% eH EeHH EeHh eeHH eeHh What fraction of F1 offspring have attached earlobes and no widow’s peak? EeHH eH EeHh eeHH eeHh eH EeHH EeHh eeHH eeHh 0%
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In rabbits, fluffy tails (F) are dominant to unfluffy tails (f)
In rabbits, fluffy tails (F) are dominant to unfluffy tails (f). Brown fur (B) is dominant to white fur (b). If two rabbits who are heterozygous for both traits are crossed, complete the cross & answer the questions. Parent Genotypes: FfBb x FfBb FB Fb fB fb What are the phenotypes of the F1 & their ratios? FB FFBB FFBb FfBB FfBb 9 fluffy/brown: 3 fluffy/white: 3 unfluffy/brown: 1 unfluffy/white Fb FFBb FFbb FfBb Ffbb FfBB fB FfBb ffBB ffBb fb FfBb Ffbb ffBb ffbb
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If a rabbit that is homozygous dominant for tails and homozygous recessive for fur is crossed with a rabbit that is homozygous recessive for tails, and homozygous dominant for fur, complete the cross and answer the questions. Parent Genotypes: FFtt x ffTT Ft Ft Ft Ft What are the phenotypes of the F1 & their ratios?? fT FfTtH FfTt FfTt FfTt 100% (16) fluffy/brown fT FfTt FfTt FfTt FfTt FfTtH fT FfTt FfTt FfTt fT FfTt FfTt FfTtH FfTt
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In pea plants, green pods are dominant to yellow, and round seeds are dominant to wrinkled. Answer the following questions using the Punnett Square below. What are the genotypes of the parents? Gr Gr gr gr Ggrr x ggRr What fraction of the F1 generation will be yellow and wrinkled? gR GgRr GgRr ggRr ggRr gr Ggrr Ggrr ggrr ggrr 4/16 = 1/4 What fraction of the F1 generation will be green and wrinkled? GgRr gR GgRr ggRr ggRr gr Ggrr Ggrr ggrr ggrr 4/16 = 1/4
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