Moutated Traits

Our group was assigned fruit flies with the mutated traits of shadow body and stubby wings. These traits were easily identifiable. A shadowed body was gray instead of the wild-type color of light brown, and stubby wings were nearly absent from the organism when they should be prominent. In this experiment, we attempted to determine the mode of inheritance for these two traits.

After the parents mated, we viewed their F1 offspring. We noticed this generation didn’t contain either of the mutated traits presented in their parents. All offspring in both the forward and reverse crosses had wild-type body colors and wild-type wing sizes. With this information we determined both traits were autosomal recessive. Here’s our reasoning:

Each parent was a true-breeder with a single mutant trait, however, neither mutation was exhibited in the F1 generation, all offspring had wild-type body colors and wild-type wing sizes. Because there was no physical difference between males and females, we could determine the traits were on an autosome and not a sex chromosome. Secondly, we knew the offspring were heterozygous since their parents were both homozygous. Therefore, since the wild-type phenotypes were present the wild-type alleles were dominant, and because the mutated traits were absent the mutated alleles were recessive. …show more content…
Due to our insufficient sample size of the F2 generation, we were unable to determine if the shadow body and stubby wing traits are present on the same autosome. The results of our Chi-square (χ2) “goodness of fit” tests explained this