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प्रश्न
Explain a dihybrid cross with suitable example and checker board method.
उत्तर
The phenotypic ratio of different types of offsprings (with different combinations) obtained in F2 generation of dihybrid cross is called the dihybrid ratio. It is 9 : 3 : 3 : 1.
For example, when we cross a yellow round seed pea plant with a green wrinkled seed pea plant, we get 9 yellow round, 3 yellow wrinkled, 3 green round and 1 green wrinkled plants in the F2 generation.
F2 generation →
 → |
YR | Yr | yR | yr |
|
|
||||
| YR | YYRR Yellow round | YYRr Yellow round | YyRR Yellow round | YyRr Yellow round |
| Yr | YYRr Yellow round | YYrr Yellow wrinkled | YyRr Yellow round | Yyrr Yellow wrinkled |
| yR | YyRR Yellow round | YyRr Yellow round | yyRR Green round | yyRr Green round |
| yr | YyRr Yellow round | Yyrr Yellow wrinkled | yyRr Green round | yyrr Green wrinkled |
↓Phenotypic ratio: Yellow round = 9 ;Yellow wrinkled = 3; Green round = 3; Green wrinkled = 1
Dihybrid ratio → 9 : 3 : 3 : 1
Genotypic ratio →
YYRR YYRr YyRR YyRr YYrr Yyrr yyRR yyRr yyrr
1 : 2 : 2 : 4 : 1 : 2 : 1 : 2 : 1
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संबंधित प्रश्न
Give the Phenotypic and Genotypic ratio of the F2 and F2 generation.
Give Technical Term:
The individuals having dissimilar pairs of genes.
Complete the following sentence with appropriate word:
______is the hereditary unit.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Mutation can be brought about artificially.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
A female is responsible for the sex of the progeny.
Multiple Choice Question
When an individual has both the genes of a contrasting character, it is said to be:
Hybrid is an offspring from a cross between genetically different parents.
Match the items given in Column I with those listed in Column II. Choose the answer with correct combination of alphabets of the two columns.
| Column I | Column II |
| A. Monohybrid cross | 1. T and t |
| B. Test cross | 2. TT |
| C. Alleles | 3. TT × tt |
| D. Homozygous tall | 4. tt |
| 5. Tt × tt |
An indvidual of genotype, Aa Bb Cc Dd is used in test cross. How many different phenotypes can appear in this progeny?
