In one species of the plant coding for color- shape and amount of wate.pdf
- 1. In one species of the plant coding for color, shape and amount of water in the fruit are on the same chromosome. The gene responsible for the color of the fruit has two alleles (R = red, r=green), the gene responsible for the shape of the fruit also has two alleles (L =long, l=round), and the gene responsible for the amount of water in the fruit also has two alleles (S dry, s=juicy). The alleles represented by capital letters are dominant over the alleles represented by small letters. Crossing a pure line plant with red, long, dry flowers with a pure line plant with green, round, juicy fruits results in an F1 plant with rough, long, dry fruits. The F1 individuals are crossed with a pure line plant having green, round and juicy fruits and an F2 is obtained composed of: 22 green, long, juicy fruits 22 red, round, dry fruits 181 red, long, dry fruits 2 green, round, dry fruits 50 green, long, dry fruits 175 green, round, juicy fruits 44 red, round, juicy fruits 4 red, long, juicy fruits i) Write the genotypes of the parents that were used to produce the F1 heterozygote. Explain, Show all calculations (4 points) a) LRS/LRS and lrs/lrs b) LRS/lrs and LRS/lrs c) L/L, R/R, s/s and l/l, r/r, S/S d) L/L, R/R, s/s and l/l, r/r, s/s e) Lrs/Lrs and lRS/lRS ii) Which of these three genes (L, R, or S) is in the medium? Explain (2 points) a) L is in the middle b) R is in the middle c) S is in the middle d) none of the above e) the answers a, b, and c are possible iii) What is the distance between the genes R and L? Show all calculations. (2 points) a) 8.8 cM b) 10 cM c) 20 cM d) 30 cM e) 35 cM iv) What is the distance between the R and S genes? Show all calculations. (2 points)
- 2. a) 10 cM b) 14 cM c) 20 cM d) 30 cM e) 35 cM iv) What is the distance between the L and S genes? Show all calculations. (2 points) a) 5 cM b) 10 cM c) 15 cM d) 20 cM e) 30 cM v) What is the coincidence coefficient? Show all calculations (2 points) a) 0 b) 0.2 c) 0.4 d) 0.6 e) 0.8