THE OFFSPRING OF A CROSS BETWEEN A PLANT WITH PURPLE FLOWERS AND A PLANT WITH WHITE FLOWERS ARE 23 PLANTS WITH PURPLE AND 26 WITH WHITE FLOWERS. USE THE LETTER P FOR PURPLE AND p FOR WHITE. WHAT R THE GENOTYPES OF THE PARENT PLANTS.
The genotypes of the parents must be Pp and pp, such that half the progeny have the dominant allele (P_) and half have the recessive phenotype (pp).
To determine the genotypes of the parent plants, we can use the principles of Mendelian genetics and the information provided. Let's represent the purple flower gene as "P" and the white flower gene as "p".
According to the given information:
- The offspring consists of 23 purple-flowered plants and 26 white-flowered plants.
- The cross is between a plant with purple flowers and a plant with white flowers.
Since the purple-flowered plants in the offspring can have either homozygous dominant (PP) or heterozygous (Pp) genotypes, and the white-flowered plants can only have the homozygous recessive (pp) genotype, we can set up two possible scenarios for the parent plants:
Scenario 1:
- Purple-flowered parent plant (Pp) × White-flowered parent plant (pp)
- Offspring genotypes: 50% Pp, 50% pp (23 plants with PP and 26 plants with pp)
Scenario 2:
- Purple-flowered parent plant (PP) × White-flowered parent plant (pp)
- Offspring genotypes: 100% Pp (all 49 plants with Pp)
Based on the information given, it is not possible to definitively determine whether the purple-flowered parent plant is homozygous dominant (PP) or heterozygous (Pp). Both scenarios are consistent with the given data.
To determine the genotypes of the parent plants, let's assign the dominant trait (purple flowers) as "P" and the recessive trait (white flowers) as "p."
From the given information, we know that the offspring consists of 23 plants with purple flowers (PP or Pp) and 26 plants with white flowers (pp).
Let's consider two possibilities for the parent plants:
1. If one parent plant has the genotype PP and the other has the genotype pp, all the offspring would be heterozygous (Pp) because the dominant allele (P) would always be expressed.
2. If both parent plants have the genotype Pp, we can use a Punnett square to determine the possible genotypes of the offspring. When two heterozygous plants are crossed (Pp x Pp), the Punnett square gives us the following possibilities:
- PP (purple) | Pp (purple) | Pp (purple) | pp (white)
- Pp (purple) | pp (white) | Pp (purple) | pp (white)
- Pp (purple) | Pp (purple) | pp (white) | pp (white)
- Pp (purple) | pp (white) | pp (white) | pp (white)
Based on the given information, we cannot definitively determine the genotypes of the parent plants. It could be either PP x pp or Pp x Pp.