biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3-7-rwngstvrgws

### <Success style="font-size:25px"> Geneticsevolution Principles Of Inheritancevariation L-3 </Success>
### <primary style="font-size:24px"> NCERT question </primary>
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- **Question 1.**

* A pea plant producing axial flower is crossed with another pea plant producing terminal flower. Among the progenies, 45 plants are producing axial flower, whereas 48 plants are producing terminal flower.
* What is the type of inheritance noticed here?
* Write the genotype of the parents and work out in a Punnett's Square.

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<footer style = "font-size: 18px">Genetics and evolution $\rightarrow$ Principles of inheritance and variation $\rightarrow$ <span style = "color:blue"> NCERT question </span> $\rightarrow$ NCERT question $\rightarrow$ NCERT question </footer>

### <Success style="font-size:25px"> Geneticsevolution Principles Of Inheritancevariation L-3 </Success>
### <primary style="font-size:24px"> Dihybrid cross </primary>
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- Dihybrid cross - Cross between two parent differing in two pairs of contrasting characters
 - **Example-** Shape of the seed and colour of the seed
- Shape of the seed - Contrasting characters are - Round and wrinkled
- Colour of the seed yellow and green
- Mendel selected a pure breeding pea plant producing round and yellow seed, and it was crossed with another plant producing wrinkled and green seed

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![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-05.jpg)

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<footer style = "font-size: 18px">NCERT question $\rightarrow$ NCERT question $\rightarrow$ <span style = "color:blue"> Dihybrid cross </span> $\rightarrow$ Dihybrid cross $\rightarrow$ Dihybrid cross </footer>

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* In the original cross, mendel selected plant producing round and yellow seed as male and wrinkled green as female
* By continuous self pollination, he produced make the pure breeding plants
* Mendel emasculated the wrinkled yellow pea flowers and converted into a female flowers
* Bagging of emasculated flowers as well as male flowers
* Collection of pollen grains from round yellow seeds
* Dusting of pollen grains into the stigma of female flower, followed by bagging
* Collection of seeds and sowing
* F<sub>1</sub> hybrids are round yellow

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![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-06.jpg)

![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-07.jpg)

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<footer style = "font-size: 18px">NCERT question $\rightarrow$ Dihybrid cross $\rightarrow$ <span style = "color:blue"> Dihybrid cross </span> $\rightarrow$ Dihybrid cross $\rightarrow$ Dihybrid cross </footer>

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### <primary style="font-size:24px"> Dihybrid cross </primary>
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- **F<sub>1</sub> on selfing to produce F<sub>2</sub> generation**

- In the F<sub>2</sub> generation, 9 round yellow, 3 round green, 3 wrinkled yellow and 1 wrinkled green were produced

- F<sub>2</sub> Phenotypic ratio of a dihybrid cross is 9:3:3:1

- The genotypic ration is 1:2:1 :: 2:4:2::1:2:1

- The cross is genetically shown as follows

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![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-07.jpg)

![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-08.jpg)

![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-09.jpg)

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| Parents| - | Male| x | female|
| -------- | -------- | -------- | -------- | -------- |
| Phenotype| - | Round yellow| | wrinkled green |
| Genotype | - | RRYY |   | rr yy |
| Gametes  | - | RY RY |  | ry ry |

- F<sub>1</sub>-dihybrid - RrYy - Round yellow

- Selfing of F<sub>1</sub> dihybrid - RrYy(male) x RrYy(female).

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![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-09.jpg)

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- Female - ry ry

- Male - RY RY rY ry

| RrYy(R.Y) | RrYy(R.Y) |  |
| -------- | -------- | -------- |
| Rryy(R.G)    | Rryy(R.G)     |
| rrYy(W.Y)    | rrYy(W.Y)     |
| rryy(W.G)    | rryy(W.G)     |

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- Round yellow = 2

- Round green = 2

- Wrinkled yellow = 2

- Wrinkled green = 2

- 1:1:1:1

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<footer style = "font-size: 18px">Dihybrid cross $\rightarrow$ Dihybrid test cross $\rightarrow$ <span style = "color:blue"> Dihybrid test cross </span> $\rightarrow$ Dihybrid back cross $\rightarrow$ Dihybrid back cross </footer>

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- F<sub>1</sub>  dihybrid × Dominant Parent

- (Female- round yellow )RrYy  ×  (Male- round yellow )RRYY

- Female - RY Ry rY ry   $\quad \quad \quad \quad \quad$          Male - RY Ry

| RY | Ry | rY | ry |
| -------- | -------- | -------- | -------- |
| RRYY(R.Y)    | RRYy(R.Y)     | RrYY(R.Y)   | RrYy(R.Y)   |
| RRYY(R.Y)    | RRYy(R.Y)     | RrYY(R.Y)  | RrYy(R.Y)   |

- Round yellow in phenotype

- Dominant in phenotype

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![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-16.jpg)

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- (Female )Tall yellow $\quad \quad$ × $\quad \quad$(Male)Tall green

- TtYy $\quad \quad$  × $\quad \quad$Ttyy

- **Gametes**
- TY ty

| TY | Ty | tY | ty |
| -------- | -------- | -------- | -------- |
| TTYy(T.Y))    | TTyy(T.G)     | TtYy(T.Y)   | Tryy(T.G)   |
| TtYy(T.Y)    | Ttyy(T.G)     | ttYy(D.Y)  | ttyy(D.G)   |

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![image](/subject-images/iitpal/image/biology-class-12-unit-05-chapter-03-geneticsevolution-principles-of-inheritancevariation-l-3_7-rwngstvrgws-18.jpg)

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