Population Genetics

tom56elliott · Post by **tom56elliott** » Tue May 27, 2008 5:29 am

Population Genetics

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Post by tom56elliott » Tue May 27, 2008 5:29 am

Prepare explanations for the following crosses so you can help others understand the possible progeny resulting from crosses between the various parents

Question 1a) Unicorns with the listed genotypes for two co-dominant coat colour alleles were crossed: Male A1A2, Female A1A2

Question 1b) If A1 was fully dominant to A2, rather than co-dominant as above, what would be the phenotypic ratio in the progeny?

Question 2. An enzyme catalyes the production of an eye colour pigment in Drosophila. The enzyme locus was localizes to chromosome 3 (2n=8 Drosophila, four homologous pairs, numbered 1 to 4). A second gene controlling wing development was localized to chromosome 2. For both genes two alleles were known: normal and defective. For each gene a particular fly was known to have have a 'normal' and a 'defective' allele. Calculate the frequency of gametes from this individual that contain two normal alleles for these particular traits.

Question 3. A sheep geneticist crossed two sheep heterozygous at two independently assorting loci that affected wool colour and the occurence of patches in the wool respectively. At both loci the normal allele was dominant to the recessive: ie black, patchy wool was a double recessive homozygote. Explain the genotypes for both parents and the expected genotype frequencies in the progeny.