Incomplete/Codominance Problem
In snapdragons the dominant allele "R" produces red flowers and its recessive form, "r" produces white flowers. Normally what would you expect for the F1 genotype and phenotype ratios if a homozygous red flower and a homozygous white flower are crossbred?
When the above cross is done the F1 generation is all pink flowers. What pattern of inheritance is illustrated by snapdragons? What are the F2 genotypic and phenotypic ratios if the F1 flowers are crossbred among themselves?
Unfortunately, we lack biology experts to help you at this time. Thank you for asking
To determine the genotypic and phenotypic ratios of the F1 generation in snapdragons, we need to understand the pattern of inheritance exhibited by these traits. In this case, snapdragons demonstrate incomplete dominance, which occurs when neither allele is completely dominant over the other. Instead, both alleles contribute to the phenotype, resulting in a blending or intermediate phenotype.
In snapdragons, the dominant allele "R" produces red flowers, while the recessive allele "r" produces white flowers. When a homozygous red flower (RR) is crossbred with a homozygous white flower (rr), we expect to see a heterozygous offspring (Rr) in the F1 generation.
The F1 generation is all pink flowers because of incomplete dominance. The blending of the red and white alleles results in a phenotype that is a mixture of both colors.
To determine the genotypic and phenotypic ratios of the F2 generation when the F1 flowers are crossbred amongst themselves, we can use a Punnett square. In this case, we will be crossing two heterozygous (Rr) individuals.
When we set up the Punnett square, we get the following genetic combinations:
R r
-------------
R | RR Rr
r | Rr rr
From the Punnett square, we can see that there are three possible genotypes: RR, Rr, and rr. However, since the phenotype of RR and Rr individuals is the same (pink flowers), the phenotypic ratio of the F2 generation is 1 pink: 2 red: 1 white.
Therefore, the F2 genotypic ratio is 1 RR: 2 Rr: 1 rr, and the F2 phenotypic ratio is 1 pink: 2 red: 1 white.