Two melanic European moths were crossed with each other. The wing colours of the offspring were $15$ typical and $41$ melanic. Construct a genetic diagram to account for these results. You may use the symbols $A$ and $a$ to stand for the alleles.
In a similar investigation, two melanic North American moths were crossed with each other. The offspring colours were $10$ typical and $31$ melanic. What conclusion can be drawn about the allele responsible for the melanic form in the moth populations on both continents?
Explain why cross 2 is a test cross.
Complete Table 10.1 to show the predicted results if: the European and North American melanic alleles are on the same locus $(A/a)$; the European and North American melanic alleles are on two different loci $(A/a$ and $B/b)$.
A light trap was used to estimate the total population size of $\textit{B. betularia}$ in a woodland. On the first night, 24 moths were caught. These were marked with a small spot of harmless paint. On the second night, 29 moths were caught, and 8 of these had a paint spot. Use the Lincoln index formula given to calculate the population size. Show your working. $N = \frac{n_1 \times n_2}{m_2}$, where $N$ is the estimate of population size, $n_1$ is the number of individuals captured in the first sample, $n_2$ is the number of individuals (both marked and unmarked) captured in the second sample, and $m_2$ is the number of marked individuals recaptured in the second sample.