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Dihybrid Inheritance.
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“ Now, we are going to look at inheritance of 2 genes at the same time.
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Example: Rabbit Coat Colour & Ear Length ➜ B – brown coat ➜ b – white coat ➜ E – long ears ➜ e – short ears.
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Possible Genotype Combinations 1. BBEE – 2. BBee – 3. BBEe – 4. BbEE – 5. Bbee – 6. BbEe – 7. - 8. - 9. -.
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Worked Example : BbEe X Bbee Parental phenotypes Parental genotypes Parental gametes.
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Ö q) 9 J -9 92 3.
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Another Example: Tomato Plant stem colour gene ➜ A = allele for purple stem ➜ a = allele for green stem leaf shape gene ➜ D = allele for cut leaves (jagged edges) ➜ d = allele for potato leaves (smooth edges).
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Question: AaDd X aadd Parental phenotypes Parental genotypes Parental gametes.
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Your turn: Heterozygous at Both Loci.
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“ The 9:3:3:1 ratio is typical of a dihybrid cross where both parents are heterozygous at both gene loci.
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Question In a species of mammal, it is known that the allele for black eyes, B, is dominant to the allele for red eyes, b, and that the allele for long fur, F, is dominant to the allele for short fur, f. a) What are the possible genotypes for an animal with black eyes and long fur? a) How could you find out which genotype this animal had?.