In a flowering plant, blue flower (B) trait is dominant to white flower (b) trait. A true-breeding blue flower plant (BB) is cro
ssed with another true-breeding white flower plant (bb). What percentage of offspring are expected to have blue flowers? Choose 1 answer: Choose 1 answer: (Choice A) A 000 percent (Choice B) B 505050 percent (Choice C) C 757575 percent (Choice D) D 100100100 percent
To begin, let us express the alleles for each trait:
Blue flower (B) (dominant)
White flower (b) (recessive)
Parents:
1. True breeding blue flower (BB)
2. True breeding white flower (bb)
Now let us do the crossing:
b b
B Bb Bb
B Bb Bb
From the cross, it is seen that out of 4 offspring, the genotypes were 'Bb' while are flowers that are phenotypically blue in color. Hence, all the offspring have blue flowers.
One parent is with is a true breeding blue flowering plants this means the two alleles of the genotype are homozygous dominant alleles (BB).
The other parent is a true breeding with flowering plant, this means the two alleles of the genotype are homozygous recessive alleles (BB).
When both parents are crossed, the possible genotype outcome is
B B * b b
Bb Bb Bb Bb
Therefore since the blue flowering plant allele (B) is dominant to the white flowering plant allele (b) the probability of an offspring outcome to be a blue flowering plant is 4/4 which is 100%.44
According to Mendelian's law of inheritance, the dominant allele is the allele that is expressed in an individual while the recessive allele are usually not expressed in the phenotype of an individual.
If a parents is dominant for a particular allele of tallness and recessive for a particular allele of shortness it is observed that the dominant allele is what is expressed in the phenotype of the offspring and inherited in simple Mendelian fashion by the offspring.
