Mendelian recombinations are due to :a)mutationb)crossing overc)pleiotrophyd)independent assortmentCorrect answer is option 'D'. Can you explain this answer?

Question

Answer

When a cross is made between two individuals different from each other in two or more characters, then the inheritance of one character is independent of the inheritance of another character. It is called Law of independent assortment. This is correct if the genes are present on two different chromosomes. Due to this, new phenotypes, appear in the F2 generations.

Answer

When two genes are close together on the same chromosome, they do not assort independently and are said to be linked. Whereas genes located on different chromosomes assort independently and have a recombination frequency of 50%, linked genes have a recombination frequency that is less than 50%.

Answer

Mendelian recombinations are due to independent assortment.

Independent assortment is a process that occurs during meiosis, specifically in metaphase I, where homologous chromosomes align randomly along the metaphase plate. This leads to the formation of genetically diverse gametes through the shuffling and recombination of alleles.

Explanation:

During meiosis, the DNA in the parent cell replicates, resulting in two copies of each chromosome called sister chromatids. In metaphase I, homologous chromosomes pair up and align along the metaphase plate. The orientation of each homologous pair is random, meaning that either the maternal or paternal chromosome can face either pole of the cell.

Key Point:
- Independent assortment occurs during metaphase I of meiosis.

Consequences of independent assortment:

Independent assortment leads to the formation of genetically diverse gametes. This is because the orientation of each homologous pair is random, and therefore, the combination of alleles on each chromosome can vary.

Key Point:
- Independent assortment leads to genetic diversity in offspring.

Example:

Let's consider a hypothetical example with two genes, A and B, located on different chromosomes. Each gene has two alleles, A and a for gene A, and B and b for gene B.

If a parent is heterozygous for both genes (AaBb), during meiosis, the homologous chromosomes can align in two different ways:

1. Maternal chromosome with allele A aligns with paternal chromosome with allele B.
2. Maternal chromosome with allele A aligns with paternal chromosome with allele b.

The resulting gametes will be AB and Ab, which are different from the parental genotype AaBb.

Key Point:
- Independent assortment allows for the creation of new combinations of alleles in offspring.

Conclusion:

Mendelian recombinations, which lead to genetic diversity, are due to independent assortment. This process occurs during meiosis, specifically in metaphase I, where homologous chromosomes align randomly along the metaphase plate, resulting in the shuffling and recombination of alleles.

Similar NEET Doubts

Mendelian recombinations are due to

Which of the following statements is true regarding the “law of independent assortment”?

Source of mendelian recombinations is

Which of the following statement is not true of two genes that show 50 percentage recombination frequency? (

Which of the following will not result in variations among siblings?

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