D.
variable-ratio schedule of reinforcement.
Answer:
The ratio of blue to white offspring in the progeny is 4 blue : 12 white.
Explanation:
<u>Available data:</u>
- The dominant allele K is necessary to synthesize blue flower pigment
- K is inhibited by the dominant allele D
- Plants with the genotype K- D- will not produce pigment (and their flowers will be white)
Cross: testcross for (Kk Dd) plants
Parental) KkDd x kkdd
Gametes) KD kD Kd kd
kd kd kd kd
Punnet square) KD Kd kD kd
kd KkDd Kkdd kkDd kkdd
kd KkDd Kkdd kkDd kkdd
kd KkDd Kkdd kkDd kkdd
kd KkDd Kkdd kkDd kkdd
- Whenever D is present, it inhibits the expression of the K gene, so every plant with the dominant D allele will be white. This plants´ genotype is kkD- or K-D-.
- Whenever D is absent and K is present, every plant with genotype K-dd will be blue.
- The recessive form for K and D genes will express white-flowered plants, with genotype ddkk
F1) Progeny genotype: 4/16 KkDd, white-flowered plants
4/16 Kkdd, blue-flowered plants
4/16 kkDd, white-flowered plants
4/16 kkdd, white-flowered plants
The ratio of blue to white offspring in the progeny is 4 blue : 12 white.
Blue-flowered plants: 4 Kkdd
White-flowered plants: 4 KkDd + 4 kkDd + 4 kkdd
