Natural selection has brought about this rise in lactose persistence. State the type of selection responsible for this increase.
Explain why humans several thousand years ago were selected for lactose persistence.
Lactose intolerance and lactose persistence were investigated in a test population in Europe. The mutation that causes lactose persistence is in a regulatory gene $(T/t)$. Individuals with lactose intolerance have genotype $tt$. Individuals with lactose persistence have genotypes $TT$ and $Tt$. A total of $166$ people were tested for their genotype. $58$ people were found to have lactose intolerance.
The Hardy-Weinberg principle can be used to determine allele, genotype and phenotype frequencies in populations. The Hardy-Weinberg equations are $p + q = 1$ and $p^2 + 2pq + q^2 = 1$. Calculate the frequency of allele $T$. Show your working.
When the calculated phenotype frequencies were compared with those in the general population in Europe, it was found that the percentage of people with lactose intolerance in this test population was much higher than in the general population. Suggest two reasons why the percentage of people with lactose intolerance was much higher in the test population than in the general population.
Outline the ways transcription factors perform their role.
It is estimated that $2\%$ of human DNA consists of genes coding for proteins (structural genes). Of the remaining $98\%$, some of the DNA consists of regulatory genes and control sequences that together control gene expression. State one type of control sequence found in human DNA.
A study of human evolution identified the location of mutations that lead to a change in human phenotype. The study found that most examples of mutations had occurred in regulatory genes, not structural genes. Suggest and explain why most changes in human phenotype are due to mutations in regulatory genes.