In a trihybrid cross, an individual with the genotype AaBbCc is crossed with another individual with the genotype aaBbCc. The F1 generation can have eight different genotypes: AaBbCc, AaBbcc, AaBbcc, AabbCc, aaBbCc, aaBbcc, aaBbcc, and aabbCc. What is the probability of each genotype P(AaBbCc) occurring?

Consider the following genotype frequencies:

ABC = 3
A++ = 54
+B+ = 215
A+C = 235
++C = 29
+++ = 5
+BC= 52
AB+= 92

How would you determine which phenotype undergoes double crossovers?

In a trihybrid cross experiment, a researcher wanted to determine the recombination frequency between three genes in fruit flies: body color (B), eye color (E), and wing size (W). The dominant alleles for these genes are black body color (B), red eye color (E), and normal wing size (W), respectively. The recessive alleles are gray body color (b), white eye color (e), and miniature wing size (w), respectively.

The researcher crossed a trihybrid fly that was heterozygous for all three genes with a fly that was homozygous recessive for all three genes. The resulting F1 generation had black body color, red eye color, and normal wing size.

The researcher then performed a series of test crosses between the F1 generation and the homozygous recessive fly for each gene separately. In terms of body color and eye color, the results are shown below:

Black body color and white eye color = 20
Gray body color and red eye color = 30
Black body color and red eye color = 45
Gray body color and white eye color = 55

What is the recombination frequency between the body color gene and the eye color gene?

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 number of double crossovers.

The following are the result of the F2 generation of a three-point cross. What is the recombination frequency of loci A,B?

A trihybrid cross was done between a male with genotype AABBCC and a female with genotype aabbcc, and their F1 progeny were selfed. Determine the phenotypic probability of F2 generation offspring having dominant phenotypes for all three traits.

A fruit fly which is heterozygous for grey body, normal wings and red eyes is crossed with a fruit fly having the same genotype. What proportion of their offspring will have homozygous grey body, normal wings and red eyes. Assume that no crossing over takes place.