Mendel’s – Law of Independent Assortment
Q: How do the genes/alleles of different characters located on the same or different chromosomes inherited by the next generations?
A. As it is B. changes with freedom C. A&B D. None
- Mendel allowed cross-pollination between two plants by taking the two pairs of different characters (Yellow-Rond X Green-Wrinkled) to get the answer for the above question!
- Yellow-Rond- dominant characters
- Green-Wrinkled- Recessive characters
- In the F1 generation, all the plants were Yellow-Rond due to complete dominance.
- Mendel allowed self-pollination between the F1 generation plants to know and derive the hidden recessive characteristics.
- Surprisingly! he got 4 varieties of phenotypes (9:3:3:1 ratio).
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What has happened in this experiment, actually?
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Mendel predicted and continued the experiments and the results were calculated and interpreted as:
- He got the 16 Genotypes (1:2:2:4:1:2:1:2:1 ratio). This is different from what Mendel expected as he would get two monohybrid ratios.
- Result: The different genes located on the homologous chromosomes involved in the Crossing over during meiosis forms the different gametes. These different gametes in different combinations formed the 16 different Genetic combinations.
- Conclusion: Genes of different characters located on the chromosomes, but those are freely or independently involved in the crossing over and formed different gametes, produced the different combinations (16) in F2 generation.
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Still, doubted?
- Yes, Mendel doubted whether the genes (factors) assorted independently or not.
- Proofing started with Test Cross!
- Mendel has chosen an F1 generation plant (dihybrid) and crossed it with the Double recessive P1 parent (Green-Wrinkled) and got the expected ratio, 1:1:1:1.
- One-word answer for the entire discussion is: Crossing over.
- For the Complete Explanation: watch this video: https://youtu.be/mFe7eAbwJGE.