Select the correct statement from the ones given below with respect to...
Tightly linked genes show no or very few recombinations, whereas loosely linked genes or genes far apart show high number of recombinations
Select the correct statement from the ones given below with respect to...
Tightly linked genes on the same chromosome show very few recombinations.
In a dihybrid cross, two different genes located on the same chromosome are considered. The term "linkage" refers to the tendency of these genes to be inherited together due to their physical proximity on the chromosome. The level of linkage between two genes determines the frequency of recombination events that occur during meiosis. Recombination, or the exchange of genetic material between homologous chromosomes, leads to the formation of new combinations of alleles.
When genes are tightly linked, meaning they are located very close together on the same chromosome, the likelihood of recombination occurring between them is significantly reduced. This is because the physical proximity of the genes makes it less likely for crossing over to happen between them. Crossing over is the exchange of genetic material between non-sister chromatids during meiosis, and it is one of the main mechanisms by which recombination takes place.
Explanation:
When genes are tightly linked, the chance of them being separated during crossing over is low, resulting in very few recombinations. This is because crossing over typically occurs between genes that are farther apart on the same chromosome. The closer two genes are to each other, the less likely they are to be separated by crossing over. Therefore, tightly linked genes show very few recombinations.
Example:
For example, let's consider two genes A and B located closely on the same chromosome. If they are tightly linked, they are likely to be inherited together without much recombination. In this case, if an individual is heterozygous for both genes (AaBb), the gametes produced during meiosis will predominantly have the parental combinations AB and ab. Only a small proportion of gametes, resulting from rare recombination events, will have the non-parental combinations Ab and aB.
Conclusion:
In summary, tightly linked genes on the same chromosome show very few recombinations. This is because their close physical proximity reduces the likelihood of crossing over and the exchange of genetic material between them during meiosis. On the other hand, genes that are far apart on the same chromosome are more likely to undergo recombination events, leading to a higher frequency of new combinations of alleles.
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