NEET BIOLOGY

GENETICS AND EVOLUTION

EVOLUTION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Why is genetic drift not a type of natural selection?
A
It’s random; not due to advantages that the individual has
B
It’s due to the environment, rather than chromosomal changes
C
Humans are involved, making genetic drift artificial selection
D
None of the above
Explanation: 

Detailed explanation-1: -Unlike natural selection, genetic drift does not depend on an allele’s beneficial or harmful effects. Instead, drift changes allele frequencies purely by chance, as random subsets of individuals (and the gametes of those individuals) are sampled to produce the next generation.

Detailed explanation-2: -Genetic drift is the change in frequency of an existing gene variant in the population due to random chance. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation. It could also cause initially rare alleles to become much more frequent, and even fixed.

Detailed explanation-3: -Genetic drift describes random fluctuations in the numbers of gene variants in a population. Genetic drift takes place when the occurrence of variant forms of a gene, called alleles, increases and decreases by chance over time.

Detailed explanation-4: -Genetic drift affects the genetic makeup of the population, but unlike natural selection, through an entirely random process. So although genetic drift is a mechanism of evolution, it doesn’t work to produce adaptations.

Detailed explanation-5: -Genetic drift can result in the loss of rare alleles, and can decrease the size of the gene pool. Genetic drift can also cause a new population to be genetically distinct from its original population, which has led to the hypothesis that genetic drift plays a role in the evolution of new species.

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