Q. 14.5( 2 Votes )
Name the law that states that the sum of allelic frequencies in a population remains constant. What are the five factors that influence these values?
• The law that states that the sum of allelic frequencies in a population remains constant is Hardy-Weinberg principle.
• It states that in a given population the frequency of occurrence of alleles of a gene is supposed to remain fixed and the same through generations.
• He represented it using the algebraic equation (p+q)2 = p2 + 2pq + q2 = 1.
• Five factors are known to affect allele frequency in populations i.e., Hardy-Weinberg equilibrium.
• These are gene migration or gene flow, genetic drift, mutation, genetic recombination and natural selection.
• Gene migration or gene flow – it is movement of alleles into a gene pool or out of a gene pool that allows gene frequencies to change in the original as well as in the new population.
• Genetic drift – If the movement of alleles into a gene pool or out of a gene pool takes place by chance it is called Genetic Drift. This always influences frequencies of alleles and is inversely proportional to the size of the population. It sometimes result in the founder effect i.e., when a small group of individuals get isolated from a larger population to form a new population.
• Mutation – A mutation is a change in the sequence of an organism's DNA. They are random and occur in all directions.
• Natural Selection – is a process in which heritable variations enabling better survival are selected and passed onto the progeny. That is nature selects only those traits which help an organism to survive in the changed conditions. Those that are not fit for survival perish (die off) in the long run leading to evolution of new species.
• Genetic recombination – Production of offspring with traits which differ from parents because of gene reshuffling or combination is called genetic recombination. This phenomenon occurs during gamete formation when chromosomes are passed from parents to progeny.
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