22. Drosophila melanogaster is a species of fruit fly commonly used to investigate patterns of genetic inheritance. Flies with a curled wing mutation have deformed wings and cannot fly. Wild-type flies have normal wings.

Fruit fly eye colour is also under genetic control. Wild-type flies have red eyes while mutant flies have white eyes.

The image below depicts two flies that carry at least one of the mutant phenotypes described above.

a)
i. Define the term wild type. (1 mark)

ii. A pure breeding fly with normal wings and white eyes is crossed with a pure breeding fly with curled wings and red eyes. All of the F1 offspring produced have curled wings and red eyes. Based on this information, use appropriate allelic notation to identify the dominant and recessive alleles for each trait. (2 marks)

b)
Several crosses between an F1 individual from part a) ii. above and a pure breeding fly with normal wings and white eyes produce the following phenotypic results.
Curled wings red eyes = 410 flies; Normal wings white eyes = 470 flies
Curled wings white eyes = 81 flies; Wild type for both traits = 79 flies
Use this information to determine if these genes are linked or unlinked. Justify your answer. (2 marks)