In watermelons, the alleles for green colored fruit (R) seeded fruit (D) yellow blossoms (B) and early blooming (E) are dominant over their respective alleles for striped fruit (r) seedless fruit (d) pink blossoms (b) and late blooming (e).
a). Symbolize a cross between a homozygous dominant and a homozygous recessive plant.
b). what are all the possible genotypes from each plant?
c). what are the genotype and phenotype of an F1 plant?
RRDDBBEE x rrddbbee
RDRBRE rdrbre
To answer these questions, we need to understand the principles of Mendelian genetics and how alleles are combined during inheritance. Let's break it down step by step:
a). Symbolize a cross between a homozygous dominant and a homozygous recessive plant:
In this case, a homozygous dominant plant means that both alleles for each trait are dominant (RRDDBBEE). A homozygous recessive plant means that both alleles for each trait are recessive (rrddbbee).
To symbolize the cross between these two plants, we can represent them as follows:
Parent 1 (homozygous dominant): RRDDBBEE
Parent 2 (homozygous recessive): rrddbbe
b). What are all the possible genotypes from each plant?
When we cross the two parent plants, we need to consider how the alleles are combined. Each parent plant contributes one allele for each trait to their offspring.
The possible genotypes from Parent 1 (RRDDBBEE) are:
- RDDBBE
- RDDBbE
- RDDBBE
- RDDBbE
- RDdBBE
- RDdBbE
- RDdBBE
- RDdBbE
The possible genotypes from Parent 2 (rrddbbe) are:
- rrddbe
c). What are the genotype and phenotype of an F1 plant?
The F1 plant refers to the first generation of offspring resulting from the cross between the homozygous dominant and homozygous recessive plants.
To determine the genotype of an F1 plant, we need to consider how the alleles from the parents combine. Since the dominant alleles (R, D, B, E) are always expressed over the recessive alleles (r, d, b, e), the genotype of the F1 plant will depend on which dominant allele it receives from each parent.
The possible genotypes of the F1 plant are:
- RDDBBE
- RDDBbE
- RDDBBE
- RDDBbE
- RDdBBE
- RDdBbE
- RDdBBE
- RDdBbE
- rdDBBE
- rdDBbE
- rdDBBE
- rdDBbE
- rdDdBBE
- rdDdBbE
- rdDdBBE
- rdDdBbE
The phenotype of the F1 plant will depend on which dominant alleles are expressed. Since green colored fruit (R) is dominant over striped fruit (r), seed fruit (D) is dominant over seedless fruit (d), yellow blossoms (B) are dominant over pink blossoms (b), and early blooming (E) is dominant over late blooming (e), the F1 plant will exhibit the dominant traits for each corresponding allele:
- Green colored fruit (R)
- Seed fruit (D)
- Yellow blossoms (B)
- Early blooming (E)
Therefore, the genotype and phenotype of the F1 plant can be represented as RDDBBE.