Respuesta :
Answer: The allele for short pea plants is masked during the F1 generation, but it is still present in the genotype.
Explanation:
- There are two types of alleles present for a given gene. One allele is the dominant allele and the other is recessive.
- Whenever a dominant allele is present it is able to mask the expression of the recessive allele. Therefore, whenever a dominant allele and recessive allele are present together (heterozygous condition) the phenotype is that of the dominant allele.
- Whenever, the phenotype of the recessive allele appears it is necessary that the recessive alleles have to be in homozygous condition.
- Thus, in the P1 generation, the short pea plants are there as there is homozygous condition (tt) and the same happens in the case of F2 generation. However, in the F1 generation, all the progenies have the genotype Tt, this is a heterozygous condition and thus, the short pea plants are not seen in F1.
- Such a condition arises when TT (tall plant) is crossed with tt (short plant) in the P1 generation.
- The diagram attached shows the punnet square for such a cross and the results of the cross is the F1 generation. As seen from the punnet square all the F1 progenies are of Tt genotype and, the phenotype of tall plants is produced as T (tall) is dominant over t(short) allele.
The allele for shortness is masked by the dominant T in the F1 generation but it exists. Option B is correct.
What is the law of Dominance?
When a dominant allele is present in the organism is it masks the traits of the recessive allele.
There are two alleles one is dominant (T) and another is recessive (t). When two pure parents cross,
The genotype of parents P1 is TT - tall and tt- short
t t P1
T Tt Tt F1
T Tt Tt
When F1 self cross,
T t P2
T TT Tt F2
t Tt tt
From the Punnet square, when the short Pea plant is present in P1 and F2 generation all the Pea plants in the first generation are heterozygous.
Learn more about Punnet square:
https://brainly.com/question/2679726
