Question

4.

In pea plant, the tall(T) trait i domiant over the dwarf (t) trait. A homozygous tall plant is crossed with homozygous dwarf plant . What are the genotype and phenotypes of the first generation? Assume complete domiance. helppp meee

Answer 1

According to the law of dominance, a trait is represented by two contrasting factors of a gene in a heterozygous individual; the allele/factor that can express itself in the heterozygous individual is called as a dominant trait. The other factor whose effect is masked by the presence of the dominant factor is called recessive factor. Thus, a cross between pure breeding tall (TT) and dwarf (tt) pea plants will obtain all hybrid tall (Tt) offspring in F1 generation. According to the law of segregation, the two factors for a trait, present together in heterozygous tall plants, do not get mixed and are separated during gametogenesis. Thus each gamete receives one allele for a trait and two types of gametes are formed, 50% gametes carry factor for dominance (T) and 50% carry the recessive factor (t). Random fusion of these gametes from two-hybrid tall plants produces tall and dwarf F2 plants in a 3:1 ratio.