Populations and Hardy-Weinberg QP.pdf - Q1.In cats, males...

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Page 2Q1.In cats, males are XY and females are XX. A gene on the X chromosome controls fur colourin cats. The alleleGcodes for ginger fur and the alleleBcodes for black fur. These allelesare codominant. Heterozygous females have ginger and black patches of fur and theirphenotype is described as tortoiseshell.(a)Explain what is meant bycodominantalleles.........................................................................................................................................................................................................................................................................................................................................................................(1)(b)Male cats with a tortoiseshell phenotype donotusually occur. Explain why.........................................................................................................................................................................................................................................................................................................................................................................(1)(c)A tortoiseshell female was crossed with a black male. Use a genetic diagram toshow all the possible genotypes and the ratio of phenotypes expected in theoffspring of this cross.UseXGto indicate the alleleGon an X chromosome.UseXBto indicate the alleleBon an X chromosome.Genotypes of offspring.................................................................................Phenotypes of offspring................................................................................Ratio of phenotypes......................................................................................(3)PhysicsAndMathsTutor.com
Page 3(d)Polydactyly in cats is an inherited condition in which cats have extra toes. The allelefor polydactyly is dominant.(i)In a population, 19% of cats had extra toes. Use the Hardy-Weinberg equationto calculate the frequency of the recessive allele for this gene in thispopulation.Show your working.Answer =............................(2)(ii)Some cat breeders select for polydactyly. Describe how this would affect thefrequencies of the homozygous genotypes for this gene in their breedingpopulations over time.

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Term
Fall
Professor
Marklevitz

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