A series of crosses is performed with fruit flies (Drosophila melanogaster) to examine inheritance of the genes vestigial (vg) and cinnabar (cn). The recessive vg allele causes small, malformed wings called vestigial wings. The recessive cn allele causes bright-red eyes called cinnabar eyes.

In the first cross, a female with wild-type wings and eyes is mated with a male with vestigial wings and cinnabar eyes. All the F₁ individuals have wild-type wings and eyes. In the second cross, female F₁ flies are mated with males with vestigial wings and cinnabar eyes. The phenotypes of 500 F₂ individuals are shown in the table.

Which of the following is the most likely explanation of the results?

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The typical dyhibrid cross between two heterozygous individuals should yield a 1:1:1:1 phenotypic ratio.

Since the expected phenotypic ratio differs significantly from the observed phenotypic ratio, genetic linkage must have occured.

If two genes are located on two different chromosomes, then they would not be linked and the observed ratio should be similar to the expected.

Mitochondria do have DNA, but the genes don't usually code for physical traits such as wing shape and eye color.

The two genes could be sex-linked, but there is not enough information to determine this.