Why is the Hardy-Weinberg law useful?

Expert Answers

An illustration of the letter 'A' in a speech bubbles

First, let's define a couple of terms.  An allele is a particular form of a certain gene.  Various genes in our DNA can be found in different forms, or alleles.  A phenotype is the visible set of traits an organism displays based on the alleles present in its DNA. 

The...

Unlock
This Answer Now

Start your 48-hour free trial to unlock this answer and thousands more. Enjoy eNotes ad-free and cancel anytime.

Start your 48-Hour Free Trial

First, let's define a couple of terms.  An allele is a particular form of a certain gene.  Various genes in our DNA can be found in different forms, or alleles.  A phenotype is the visible set of traits an organism displays based on the alleles present in its DNA. 

The Hardy-Weinberg law states that in the absence of outside influences such as mutation or genetic drift, the allele and genotype frequencies will remain constant over time as the population of organisms being studied reproduces over time.  In other words, the frequency of alleles and genotypes produced in successive generations can be reliably predicted with each successive generation under idealized settings.  This utilizes the Punnett squares often seen when talking about genetic frequencies. 

As you know, however, ideal conditions are rarely found in nature.  Populations of organisms evolve genetically over time and produce new and different shifts in allele frequencies and observed phenotypes, preferring some and discarding others (evolution).  So monitoring the actual genetic frequencies of a population and comparing it to the idealized outcome predicted by Hardy-Weinberg allows geneticists to determine if a population is evolving or not.

Approved by eNotes Editorial Team