Genetics of Transmission of Traits in a Population - Essay Example

Mutation brings modification in the genes, they are capable of altering the genetic sequence and hence they alter or modify the characteristic of the organism. Some of the mutations are silent and do not bring chances in the exonic sequence of the DNA, hence they remain silent. In certain cases, these silent mutations may be expressed in the next generation or are lost in the individual. Thus, mutation or modifications of genomic sequences affects the expression of the genes in a given population. Equilibrium is observed for every inheritable modification and is studied with the help of Hardy-Weinberg equilibrium. H-W equilibrium provides the basis to analyze the alleles of the gene(s).

If no modification occurred, the static allele frequency, and crossways generations, remain static. For instance, in the present case, characteristics of the earlobe, either attached or unattached could be studied as the simple case of a single locus. The alleles are present on the single locus in two different forms namely; the dominant allele is denoted by E and the recessive by e with frequencies denoted by p and q respectively. Frequency of E freq (E) = p and frequency of e, freq(e)= q. In a given population, under ideal conditions p + q =1

On random mating, individuals may display freq (EE) = p2 for the EE homozygote in the population. On the other hand, freq (ee) = q2 for the ee homozygotes.

            The heterozygotes according to Hardy-Weinberg equilibrium, freq (Aa) = 2pq. According to Hardy-Weinberg equilibrium, p2 + 2pq + q2 = 1 (p is the dominant allele and q is the recessive allele).      Punnett square for Hardy-Weinberg equilibrium.

        Male Female

E

e

E

EE (p2)

Ee (PQ)

e

Ee (PQ)

Ee (q2)

q = recessive allele frequency; q2 is the recessive homozygous allele responsible for the attached earlobe. In the present case, the value of q2 is 25/100 or 0.25,

Since, q2 is 25/100 or 0.25, q = √0.25 =0.5. Thus, the value of the recessive allele, q = 0.5,

 p + q = 1; Therefore, p = 1- q. The value of p calculated is p = 1- 0.5

1. The frequency of unattached earlobe i.e. p = 0.5

The frequency of the attached earlobe i.e. q = 0.5

1. The estimated frequencies of heterozygous genotype = 2pq

Therefore, 2pq = 2 X 0.5 X 0.5 = 0.25

1. Frequency of dominant phenotype = p2 = 0.5 x 0.5 = 0.25

Hardy-Weinberg equilibrium explains the genetics of transmission of traits in a population. The equation explains the prevailing frequency of allelic forms of the earlobe, attached or unattached, and hence the equation is highly significant.