Multiple Cross Overs and Interference Practice Problems

When crossovers in one region of the chromosome affects the chance of crossover in an adjacent region, it is called:

In Drosophila, sepia eyes (se), curled wings (cu) and ebony body (e) are encoded by recessive genes found on chromosome 3. A researcher crosses se cu e/ + + + females with se cu e/ se cu e males and obtains the following progeny data:

The frequency of crossing over is 22% for genes se and cu and 16.6% for genes cu and e. Determine the interference value for this data set.

In Drosophila, sepia eyes (se), curled wings (cu) and ebony body (e) are encoded by recessive genes found on chromosome 3. A researcher crosses se cu e/ + + + females with se cu e/ se cu e males and obtains the following progeny data:

Determine the coefficient of coincidence across this region when the frequency of crossing over is 22% for genes se and cu and 16.6% for genes cu and e.

A purple and tall flower (PpTt) is crossed with a white and short (pptt) flower. This dihybrid cross results in the following offspring:

   PpTt: 380
   pptt: 401
   Pptt: 102
   ppTt: 117

What is the recombination frequency of the dihybrid cross?

A female Drosophila with genotype c d +/+ + e has produced a number of gametes. Which of the following gamete is a product of a single crossover?

Suppose there are three genes (X, Y, and Z) that are linked in a chromosome. If the frequency of crossing over for genes X and Y is 30% and the frequency of crossing over for genes Y and Z is 10%, what is the frequency of a double crossover between the genes X and Z assuming there is no interference?

Given the following parental gametes, identify which of the choices shows a recombinant resulting from a double crossover.