Question

You suspect that two easily identifiable traits in humans are linked. How would you determine if they truly are linked?

Answer 1

Sex linked identifiable traits: These traits are completely under the control of the genes existing on the 23 rd pair of the sex chromosome in humans, those sex chromosomes are X and Y. The remaining are autosomes, these chromosomes are involving in identifying or determining the sex linked traits. The sex linked identifiable traits are inherited through either X chromosome or Y chromosome but predominantly through X chromosome. For instance, in case of color blindness (red and green) in humans is mainly because of the inheritance controlled by a recessive allelic frequencies at the either of the 2 sites of X-chromosome.

The linkage equilibrium and disequilirium completely rely upon process of independent assortment which is explained below.

Linkage disequilibrium is 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 choromosomal genes are located at different regions on the different chromosome as a result of independent assortment. If the genes are located closely together on the same chromosome then those genes are considered to be as genetically linked and as they are not assorted independently then the recombination frequency value is less than 50%.