One of Mendel’s crosses is described in Figure 4.10 in Lewis. (IMAGE ATTACHED) a

Question

One of Mendel’s crosses is described in Figure 4.10 in Lewis. (IMAGE ATTACHED)

a. List the F2 genotypes and their proportions from Mendel’s dihybrid cross shown in Figure 4.10.

b. List the four types of gametes and their proportions (in percent) that resulted in the F2 offspring, and classify them as parental or recombinant.

c. List the four types of gametes and their proportions (in percent) if these genes had been on the same chromosome, 20 map units apart.

rryy Round Wrinkled ry ry yellow green (RRYY) I (my) RY RrYy RrYy RRYY RY All F1 plants round yellow (Rrry) RrYy RrYy F1 cross Dihybrid cross RrYy RY Ry ry RY F2 315 Round yellow R Y 108 Ry Round green R yy RRYy RRyy RrYy Rryy Test 101 crosses rY Wrinkled yellow rrY RrYY RrYy rrYy 32 Wrinkled green rryy ry RrYy rrYy Rryy rryy 9:3:3:1

Explanation / Answer

Answer:

a).

RRYY = 1/16

RRYy = 2/16

RrYY = 2/16

RrYy = 4/16

RRyy = 1/16

Rryy = 2/16

rrYY = 1/16

rrYy = 2/16

rryy = 1/16

b).

RY = Parental gametes (25%)

Ry = Parental gametes (25%)

Ry = Recombinant gametes (25%)

rY = Recombinant gametes (25%)

c).

Distance between the genes (map units) = Recombination frequency (%)

20 map units = 20% recombinants

RY = Parental gametes (40%)

Ry = Parental gametes (40%)

Ry = Recombinant gametes (10%)

rY = Recombinant gametes (10%)

d).

RF of gamete, RY = 0.4

RF of gamete, ry = 0.4

RF of gamete, Ry = 0.1

RF of gamete, rY = 0.2

F2 genotypes and their proportions are as follows.

RY(0.4)

Ry(0.1)

rY (0.1)

ry(0.4)

RY(0.4)

RRYY (0.16)

RRYy (0.04)

RrYY (0.04)

RrYy (0.16)

Ry(0.1)

RRYy (0.04)

RRyy (0.01)

RrYy (0.01)

Rryy (0.04)

rY (0.1)

RrYY (0.04)

RrYy (0.01)

rrYy (0.01)

rrYy (0.04)

ry(0.4)

RrYy (0.16)

Rryy (0.04)

rrYy (0.04)

rryy (0.16)

RRYY = 0.16 = 16%

RRYy = 0.4 + 0.4 = 0.8 = 8%

RrYY = 0.4 + 0.4 = 0.8 = 8%

RrYy = 0.16 + 0.01+ 0.01 + 0.16 = 0.34 = 34%

RRyy = 0.01 = 1%

Rryy = 0.4 + 0.4 = 0.8 = 8%

rrYY = 0.01 = 1%

rrYy = 0.04 + 0.04 = 0.08 = 8%

rryy = 0.16 = 16%

RY(0.4)

Ry(0.1)

rY (0.1)

ry(0.4)

RY(0.4)

RRYY (0.16)

RRYy (0.04)

RrYY (0.04)

RrYy (0.16)

Ry(0.1)

RRYy (0.04)

RRyy (0.01)

RrYy (0.01)

Rryy (0.04)

rY (0.1)

RrYY (0.04)

RrYy (0.01)

rrYy (0.01)

rrYy (0.04)

ry(0.4)

RrYy (0.16)

Rryy (0.04)

rrYy (0.04)

rryy (0.16)

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.