Draw a preliminary linkage map of the three loci. What is their order? (E.g. is the forked locus between yellow and cross-veinless, or outside this region?) . 

As this is a preliminary linkage map - do not account for double crossovers. You should base the distances on this map off your map distances calculated in Q4. Provide map distances to one decimal place.

Either scan or take a photo of the map, and upload it to Moodle as a JPEG.

Now fill in the two by eight Punnett square containing the male and female gametes from the F1 parents with the expected genotypes of the F2 progeny resulting.

At this stage it will be clear that the three genes are linked to each other on the X chromosome. The male gametes will bear either an X chromosome or the Y chromosome. On the other hand, the female gametes will bear X chromosomes carrying one of eight combinations of alleles of the three genes. Two of the eight will be parental (P) combinations, and six recombinant (R) combinations. Label the genotypes that correspond to recombinant combinations on your Punnett square. The latter have arisen from meioses in which cross-overs have occurred between the loci of the three genes in the female F1 flies.  (Remember we are considering the products of meiosis from the triply heterozygous F1 female, and "parental" relates to P1 and P2 parents).

IMPORTANT: When completing this table, make sure that you follow these instructions:

1. List the alleles in the order of yellow (y) forked (f) cross veinless (cv) as in the example "yfcv".  
2. Indicate the wild type allele by using a (+), such as y+f+cv would indicate wild type yellow and forked, mutant cross-veinless. 
3. When completing the progeny genotype, always list the female X genotype first.
4. Don't use any spaces or other symbols in your answers

For a given trihybrid testcross, the expected number of double recombinants is 20 and the observed number is 10. What is the coefficient of coincidence?

Enter your answer with one decimal place.

When observing your data, the phenotypic classes of offspring representing double crossovers will always:

Based on the coefficient of coincidence calculated for the previous question, what would be be your conclusion about the effect of one recombination event on the other?

In a dihybrid (two point) test cross, a double heterozygote fly (AaBb) is crossed to

Two genes that are 60 map units apart are expected to show: