# Some people crossed a mutant parental ?y with a wild—type parental ?y. An example of this is sepia females x wildtype males. All of the F1 offspring were wild—type. When the F1 offspring were crossed, the F2 included: 29 wild—type flies (14 males, 15 females) 11 sepia ?ies (4 male, 7 female) Calculate the offspring ratio of wild—type: sepia. Is this what you would have expected? Explain your reasoning. The Offspring Ratio of Wild-Type to Sepia in a Mutant Parental Fly x Wild-Type Parental Fly Cross

The Offspring ratio of Wild-Type to Sepia from a Mutant Parents Fly Cross

If a mutant parental fly is crossed (sepia womens), it is possible to produce a 1:1 offspring of wild-type and sepia. The F2 cross produced 29 wild-type (14 males and 15 females) offspring, as well 11 sepia (four males and seven females) offspring. The final offspring ratio for wild-type to sepia is 2.63:1, slightly less than the 1:1 ratio. This cross has a higher ratio than anticipated due to genetic dominance. The wild-type sepia genotype is predominant in this cross. This means that the wild-type wild-type phenotype can only be expressed if there is one wild-type variant (Bogdanove (2018)). The sepia genotype can only be expressed when both sepia alleles exist. It is because the F2 offspring produced more wild-type flies that sepia ones. This cross produced a higher offspring ratio than was expected. However, it can be explained in part by the dominance genetically of the wild type allele. This is a common phenomenon across many genetic crosses and it serves to remind us of how important it is to understand the basics of genetic inheritance (Khan 2021). Cont….