1. A true breeding tall pea line is crossed with atrue breeding short line. The F1 plants are all short. The F1 arecrossed with themselves to produce an F2. If the difference (tallvs. short) is due to a single locus, what proportion of the F2individuals do you expect to be tall?
2. Imagine that a researcher crossed the peas in theexample above, and counted 100 F2. 86 were short. 14 were tall. Doa chisquare test to see whether the results conform to a singlelocus cross with the allele coding for short plants dominant to theallele coding for tall plants.
3. A clematis from a true-breeding line with whiteflowers and short corollas (line A) is crossed to a clematis from atrue-breeding line with deep red flowers and long corollas (lineB). The resulting offspring, the F1, are all pink-flowered, withcorollas of medium length. An individual from the F1 iscrossed to an individual from line A. The resulting F2 offspringare as follows: 25% white flowers and short corollas, 25% whiteflowers with medium corollas, 25% pink flowers with short corollas,25% pink flowers with medium corollas.
What is the most likely genetic mechanism determining flower colorand corolla length? If a plant from the F1 listed above were selfed(crossed with itself), what proportion of the F2 offspring wouldyou expect to be white flowered with short corollas?
4. A man and a woman walk into a genetic counselorâsoffice. They have just had a child diagnosed with situs inversus, acomplete transposition of the internal organs from left to right,and vice versus. This condition usually produces no obvioussymptoms. It is caused by an autosomal recessive allele. What isthe chance that their next child will have the same condition? Whatmight this suggest about the parents?
Another man and woman walk into the same office. The father is anachondroplasic dwarf. The mother is of normal stature. (Look upachondroplasia, it is a lethal dominant). What is the chance thattheir first child will be a dwarf?
Please show work! (:
1. A true breeding tall pea line is crossed with atrue breeding short line. The F1 plants are all short. The F1 arecrossed with themselves to produce an F2. If the difference (tallvs. short) is due to a single locus, what proportion of the F2individuals do you expect to be tall?
2. Imagine that a researcher crossed the peas in theexample above, and counted 100 F2. 86 were short. 14 were tall. Doa chisquare test to see whether the results conform to a singlelocus cross with the allele coding for short plants dominant to theallele coding for tall plants.
3. A clematis from a true-breeding line with whiteflowers and short corollas (line A) is crossed to a clematis from atrue-breeding line with deep red flowers and long corollas (lineB). The resulting offspring, the F1, are all pink-flowered, withcorollas of medium length. An individual from the F1 iscrossed to an individual from line A. The resulting F2 offspringare as follows: 25% white flowers and short corollas, 25% whiteflowers with medium corollas, 25% pink flowers with short corollas,25% pink flowers with medium corollas.
What is the most likely genetic mechanism determining flower colorand corolla length? If a plant from the F1 listed above were selfed(crossed with itself), what proportion of the F2 offspring wouldyou expect to be white flowered with short corollas?
4. A man and a woman walk into a genetic counselorâsoffice. They have just had a child diagnosed with situs inversus, acomplete transposition of the internal organs from left to right,and vice versus. This condition usually produces no obvioussymptoms. It is caused by an autosomal recessive allele. What isthe chance that their next child will have the same condition? Whatmight this suggest about the parents?
Another man and woman walk into the same office. The father is anachondroplasic dwarf. The mother is of normal stature. (Look upachondroplasia, it is a lethal dominant). What is the chance thattheir first child will be a dwarf?
Please show work! (:
