IMAT 2016 Q27 [Random Processes]

Which of the following can be random processes?

  1. genetic drift
  2. mutations
  3. artificial selection

A. 2 and 3 only
B. 1, 2 and 3
C. 1 and 2 only
D. none of them
E. 1 and 3 only

The correct answer is C.

What is genetic drift ?

Genetic drift is the phenomenon in which the frequency of alleles in a population changes. It is random and can be caused by 2 events :

  1. bottleneck effect = the size of the population is drastically reduced (like due to an earthquake, tsunamis etc.)
  2. founder effect : a small chunk of a population breaks off from the bigger population, where the allele frequency is different

What are mutations ?

Mutations can happen randomly when there is an error in the DNA sequence after replication. It can be caused by :

  1. radiation
  2. chemicals
  3. infectious agents

What is artificial selection ?

First things first, the fact that we talk about “artificial” means it isn’t a random process. So you can already eliminate this item from that only.

Second, what is it for ? It is the process through which humans pick and choose the traits they want to perpetuate in a species.

The easiest exemple would be dog breeds : if a dog has a desirable trait, it will be selected for future breeding to ensure the enhancement of that trait.

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