Advertisements
Advertisements
प्रश्न
Given below are the F2 – phenotypic ratios of two independently carried monohybrid crosses :
(i) 1 : 2 : 1
(ii) 3 : 1
Mention what does each ratio suggest.
उत्तर
(i) 1 : 2 : 1 - Phenotypic ratio
Suggest that the phenomenon is incomplete dominance
* When neither of the alleles of a character is completely dominant over the other and the F1 hybrid is intermediate between the two parents, the phenomenon is Incomplete dominance.
* The phenotypic and genotypic ratio in F2 generation is 1:2:1 in this case.
(ii) 3:1 - Phenotypic ratio
Suggest that the phenomena has monohybrid cross. Monohybrid cross is a cross which involves only a single pair of contrasting characters. The parental generation has genotype for pure gene which on cross produces homozygous progeny i.e. F1 generation. On selfing F1 generation obtain F2 generation. The F2 generation has phenotypic ratio 3 : 1.
APPEARS IN
संबंधित प्रश्न
Differentiate between the following -
Homozygous and Heterozygous
Differentiate between the following -
Monohybrid and Dihybrid.
Differentiate Between Monohybrid and Dihybrid cross.
Name the conditions when both the alleles are identical?
What do you understand by the terms phenotype and genotype?
A pure tall plant (TT) is crossed with the pure dwarf plant (tt), what would be the F1 and F2 generations? Explain.
In a monohybrid cross of plants with red and white flowered plants, Mendel got only red-flowered plants. On self-pollinating these F1 plants got both red and white flowered plants in 3:1 ratio. Explain the basis of using RR and rr symbols to represent the genotype of plants of parental generation.
In a plant tallness is dominant over dwarfness and red flower is dominant over white. Starting with the parents work out a dihybrid cross. What is standard dihybrid ratio? Do you think the values would deviate if the two genes in question are interacting with each other?
In a cross between red coloured and white coloured flowers, when plants with red coloured flowers of F1 generation were self pollinated, plants of F2 generation were obtained in which 75% of plants were with red flowers and 2.5% plants were with white flowers.
Explain the inheritance of traits in the above cross with the help of a flow chart only along with the ratio of plants obtained.
