Which of the following is true for two genes undergoing independent as...
Only those genes which are located on different chromosomes undergo independent assortment. Those genes which are located on the same chromosome are said to represent a linkage group and are inherited together. They experience independent assortment only if they are located far apart and crossing over can occur between them.
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Which of the following is true for two genes undergoing independent as...
Independent assortment
Independent assortment is a principle of Mendelian inheritance that states that the alleles of two (or more) different genes segregate independently of one another during the formation of gametes. This means that the inheritance of one gene does not influence the inheritance of another gene.
Explanation of the answer
The correct answer is option 'A': The genes are located on different chromosomes or they are located far apart on the same chromosome. This is because genes located on different chromosomes or genes located far apart on the same chromosome are more likely to undergo independent assortment. Let's break down the explanation further:
Genes located on different chromosomes
When two genes are located on different chromosomes, they are physically separated and their inheritance is not directly linked. During gamete formation, each chromosome independently aligns at the metaphase plate and segregates randomly. As a result, the alleles of one gene segregate independently of the alleles of the other gene, leading to independent assortment.
Genes located far apart on the same chromosome
Even when two genes are located on the same chromosome, if they are far apart from each other, recombination events such as crossing over can occur between them. Crossing over is the exchange of genetic material between homologous chromosomes during meiosis. It leads to the shuffling of alleles between the two chromosomes and creates new combinations of alleles. When genes are far apart on the same chromosome, the frequency of crossing over events is higher, increasing the chances of independent assortment.
Other options
- Option 'B' states that the expression of one gene does not affect the expression of the other. While this is generally true for genes undergoing independent assortment, it does not necessarily imply independent assortment. Genes can be linked and still have independent expression.
- Option 'C' states that the genes are located at least 10cM apart on the same chromosome. While genes located far apart on the same chromosome are more likely to undergo independent assortment, there is no specific distance requirement such as 10cM.
- Option 'D' states that crossing over does not occur between the genes. This is incorrect because crossing over can occur between genes, especially when they are far apart on the same chromosome.
Therefore, the correct answer is option 'A': The genes are located on different chromosomes or they are located far apart on the same chromosome.