1
Question
In an organism, tall phenotype is dominant over recessive dwarf phenotype and the alleles are designated as T and t, respectively. Upon crossing two different individuals, total 250 offsprings were obtained, out of which 124 displayed tall phenotype and rest were dwarf. Thus, the genotype of the parents were
In an organism, tall phenotype is dominant over recessive dwarf phenotype and the alleles are designated as T and t, respectively. Upon crossing two different individuals, total 250 offsprings were obtained, out of which 124 displayed tall phenotype and rest were dwarf. Thus, the genotype of the parents were
Open in App
Solution
The correct option is C Tt × tt
Law of segregation states that the two factors for a trait, present together in a heterozygous individual (Tt here), 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). These gametes are then randomly fused to produce both dominant and recessive offspring. In order to obtain both recessive and dominant offspring, both parents should be heterozygous. Due to the absence of allele for dwarfism, a cross between two pure breeding tall varieties (TT x TT) obtains only tall but no dwarf offspring. A cross between two pure breeding tall and dwarf varieties produce heterozygous tall (Tt) offspring wherein the expression of recessive allele (t) is masked by the presence of the dominant allele (T). A cross between Tt and tt produces both tall and dwarf offspring in 1 : 1 ratio. Thus, the correct answer is option D.
Law of segregation states that the two factors for a trait, present together in a heterozygous individual (Tt here), 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). These gametes are then randomly fused to produce both dominant and recessive offspring.
In order to obtain both recessive and dominant offspring, both parents should be heterozygous. Due to the absence of allele for dwarfism, a cross between two pure breeding tall varieties (TT x TT) obtains only tall but no dwarf offspring.
A cross between two pure breeding tall and dwarf varieties produce heterozygous tall (Tt) offspring wherein the expression of recessive allele (t) is masked by the presence of the dominant allele (T).
A cross between Tt and tt produces both tall and dwarf offspring in 1 : 1 ratio.
Thus, the correct answer is option D.
Suggest Corrections
0
Similar questions
View More
Join BYJU'S Learning Program
Explore more
Join BYJU'S Learning Program
