Question

In which condition does the gene ratio remain constant in a species?
(a) Gene flow
(b) Mutation
(c) Random mating
(d) Sexual selection

Answer 1

Hint: Gene ratio remains constant and stable from generation to generation when the individual in a population interbreed without restrictions; individuals can move freely within their habitat, possibly over a range of hundreds to thousands of miles and thus breed with other members of a population.

Complete answer:
In genetics, random mating is not influenced by any environmental, hereditary, or social interaction. Hence, potential mates have equal chances of being selected. Random mating is a factor assumed by the Hardy- Weinberg principle and it is different from lack of natural selection.
The Hardy- Weinberg principle states that the population is set to be in genetic equilibrium if it is not undergoing any kind of evolutionary change. Genetic equilibrium means that the frequency of occurrence of alleles of a gene is supposed to remain fixed and even remain the same through generations.
The Hardy- Weinberg principle stated it using algebraic equations. Main concepts of these principles are: - This principle says that allele frequencies in a population are stable and are constant through generations to generations through random mating. - The gene pull (total genes and alleles in a population) remains constant. This is called genetic equilibrium. - The total allelic frequency is 1. - For example, in a population of diploid organisms, A gene has two alleles Aa. The frequency of allele A is p and of a is q. The frequency of aa individuals in this population is q² and for AA it is p². Thus, the frequency of Aa individuals is 2pq. - Hardy- Weinberg principle says that the total of all the allelic frequencies of a gene is 1 and the possible frequencies of the above-mentioned genotypes i.e. AA, aa, and Aa are p², q², and 2pq respectively. Thus, mathematical interpretation is p² + 2pq + q² = 1 i.e. (p+q) ²
So, the correct answer is, ‘Random Mating.’

Note:
- As time progresses, natural selection and genetic drift slowly move each population towards genetic differentiation that would make each population genetically unique and lead to speciation.