An investigation was carried out on the genetic and environmental influences on fruit mass in the tomato (Solanum lycopersicum).
Plants of a large-fruited 'Giant-beef' strain and a dwarf-fruited 'Micro-cherry' strain were grown under identical glasshouse conditions. The masses of six individual fruits from different plants of each strain were recorded.
The results are shown in the table below:
Tomato strain123456MeanGiant-beef185.4192.1178.6189.0195.3183.4187.3Micro-cherry12.113.511.814.212.713.112.9\begin{array}{|l|c|c|c|c|c|c|c|} \hline \textbf{Tomato strain} & \textbf{1} & \textbf{2} & \textbf{3} & \textbf{4} & \textbf{5} & \textbf{6} & \textbf{Mean} \\ \hline \textbf{Giant-beef} & 185.4 & 192.1 & 178.6 & 189.0 & 195.3 & 183.4 & 187.3 \\ \hline \textbf{Micro-cherry} & 12.1 & 13.5 & 11.8 & 14.2 & 12.7 & 13.1 & 12.9 \\ \hline \end{array}Tomato strainGiant-beefMicro-cherry1185.412.12192.113.53178.611.84189.014.25195.312.76183.413.1Mean187.312.9Which of the following statements correctly explains these results?
The variation in fruit mass between the two strains is discontinuous and controlled by one or two genes.
The variation in fruit mass between the two strains is continuous and polygenic.
The variation in fruit mass within each strain is discontinuous and polygenic.
The variation in fruit mass within each strain is continuous and controlled only by one or two major genes.
32 exam-style questions on OCR A A Level Biology Patterns of inheritance. Each one has a worked solution and a mark scheme showing where the marks go.