In Drosophila (fruit flies) the genes how,dumpy and ebony are located on chromosome 3. LOF= loss of function.

• Flies homozygous for a LOF mutation (no gene product made) inebony have dark black bodies.
• Flies homozygous for a LOF mutation (no gene product made) indumpyhave truncated (short) wings.
• Flies homozygous for a partial LOF mutation (some gene productmade but significantly less than normal) in how have wingsthat will not fold down (held outwings; that's where the gene name is coming from,how).

Use the following allele/phenotype designations:

For how

• allele h+ = wild type/normal
• allele h = partial loss of function mutation
• h+ > h
• phenotype h+ = wild type = wings that fold, which is dominantto held out wings = phenotype h

For dumpy

• allele dp+ = wild type/normal
• allele dp = LOF mutation
• dp+ > dp
• phenotype dp+ = wild type = normal wing size, which is dominantto truncated wings = phenotype dp

For ebony

• allele eb+ = wild type/normal
• allele eb = LOF mutation
• eb+ > eb
• phenotype eb+ = wild type = normal body colour, which isdominant to black body = phenotype eb

You cross a wild type female fruit fly that is a heterozygouscarrier for all three mutant alleles with a black bodied male whohas truncated wings that do not fold down.

You observe their 504 offspring and note theirphenotypes and the number of offspring with eachphenotype:

• wings that do not fold - 129
• truncated wings - 83
• black body - 6
• wings that do not fold and a black body - 80
• truncated wings that do not fold - 10
• truncated wings and a black body - 135
• truncated wings that do not fold, and a black body - 15
• wild type - 14

Note: that non-mutant phenotypes are generallyignored. For example a phenotype of \"black body\" means a fly with ablack body, normal wing length and wings that fold.

Flies homozygous for a partial LOF mutation (some gene productmade but significantly less than normal) in how have wingsthat will not fold down (held outwings; that's where the gene name is coming from,how).

But there is another mutation in how that is a complete loss offunction (no gene product made). The complete LOF mutation isrepresented as h-; h- is recessive lethal. Flies homozygous for thecomplete loss of function mutation (h-/h-) die when trying toemerge from their pupal cases. Basically, you won't see h-/h- adultflies because they are all dead.

You mate two wild type flies who are both carriers for thedumpy LOF mutation (dp) and the complete LOF howmutation (h-). They both have the same genotype: h- dp / h+dp+.

Q. How many of the resulting larvae (offspring) will beh- / h-, if the genotype at dumpy doesn't matter?Remember, the complete loss of function mutant dies when coming outof its pupal case, the larval stage is before the pupalstage.

Select one:

a. 1/4

b. 0

c. 1/2

d. 1/500