What is the effect of linkage on the inheritance of genes Ex

What is the effect of linkage on the inheritance of genes? Explain how linkage decreases the amount of genetic variation in the offspring:

Solution

Ques-1:

Answer:

Linked genes due to linkage often do not obey Mendel\'s laws of inheritance such as independent assortment because of crossing over with reciprocal exchange of hereditary genetic material meticulously in between non-sister chromatids at the time of synapsis formation in reduction division or meiosis 1. These events are leading to formation of gamete cells with complete different genotypically from diploid parent reproductive cell via meiosis finally induce genetic variation in phenotype.

Linkage disequilibrium defined as the existence of alleles at different loci with the absence of genetic linkage between them even though there is no equilibrium with allelic frequencies independently. The recombination frequency is the measure of genetic linkage at different loci. The value of recombination frequency is 50% if the chromosomal genes are located at different regions on the different chromosome because of independent assortment. If the genes are located closely together on the same chromosome, then those genes considered as genetically linked; because they have not assorted independently, then the recombination frequency value is less than 50%.

Crossing over decreases genetic linkage result in genes inherited from parents to offspring due to homologous recombination of chromosomes.

There is a scenario i.e. “double cross over in which there is no genetic recombination occurred result in no genetic diversity of genetic variation. This scenario is often referred as “2-strand double cross over” in which primarily chromatids are involved in which alleles are exchanged initially but “exchanges them back” finally producing there is no “complete or net genetic recombination”.