With the help of an algebraic equation, how did Hardy-Weinberg explain that in a given population the frequency of occurrence of alleles of a gene is supposed to remain the same through generations?

OR

Although a prokaryotic cell has no defined nucleus, yet DNA is not scattered throughout the cell. Explain.

G.H. Hardy and W. Weinberg together proposed the Hardy-Weinberg principle, which states that if a population is not undergoing any kind of evolutionary change, it is said to be in genetic equilibrium. The term “genetic equilibrium” means that the frequency of occurrence of alleles of a gene remains fixed and same throughout generation to generation. It implies that allele frequencies in a population are stable and the gene pool (total genes and their alleles) of a population remains constant. This principle also states that the sum total of all the allelic frequencies of a gene is 1.

Hardy and Weinberg used an algebraic equation to explain this:

P² + 2pq + q² = 1

Where, p = frequency of the dominant allele

q = frequency of the recessive allele

pq = frequency of heterozygotes

This equation is a binomial expansion of (p + q)².

Five factors affect the Hardy-Weinberg equilibrium:

•Gene flow

•Genetic drift

•Mutation

•Natural selection

•Genetic recombination

Any change in frequency of alleles in a population results in evolution.

OR

In prokaryotes, DNA is not scattered throughout the cell although they do not have a defined nucleus. DNA is found lying centrally in the cytoplasm in a condensed form. The coiled DNA is maintained in place by non-histone basic proteins having positive charge. DNA being negatively charged is held by these basic polyamines and this region is termed as nucleoid or genophore. The DNA is packed in large loops in the nucleoid.

A PROKARYOTIC CELL SHOWING NUCLEOID