Suggest, with reasons, whether the difference in milk yield between the first lactation and second lactation shown in Table 2.1 is genetic or environmental.
The change at position 5752 in the gene coding for a growth factor is caused by a substitution mutation from G to C. With reference to Table 2.1, describe the importance of the substitution from G to C.
Use the Hardy-Weinberg principle to estimate how many goats with genotypes CC and CG are in this Xinong Saanen population.
In a population of 268 Xinong Saanen goats: • the frequency of the C allele ($q$) is $0.30$ • the frequency of the G allele ($p$) is $0.70$ The Hardy-Weinberg principle may be applied to predict how many goats have CC, CG and GG genotypes in this population, using: $p^2 + 2pq + q^2 = 1$ For instance, the expected number of GG goats can be estimated as 131.
If the figures you predicted in b(i) closely match the actual figures in Table 2.2, that would indicate that the Xinong Saanen population is in Hardy-Weinberg equilibrium. State the name of a statistical test that could be used to determine whether the Xinong Saanen population is in Hardy-Weinberg equilibrium.
The Hardy-Weinberg principle gives the following predicted numbers of goats for the Guanzhong population: • CC = 16 • CG = 135 • GG = 289. These predicted values are significantly different from the actual values in Table 2.2. Using Table 2.2, describe the evidence showing that the Guanzhong population is not in Hardy-Weinberg equilibrium and suggest reasons for this.
Goats can be genetically modified so that human proteins are produced in their milk. In 2009, an anti-clotting protein made in this way was approved for use as a drug in people who lack the protein. State one ethical advantage and one ethical problem of producing medicinal drugs from the milk of genetically modified goats. advantage ………………… problem …………………