Question

What type of physical mutations are most likely to cause an amorph? O A nonsense 0 B missense - nonsynomous 0 C missense - synomous O D silent O E polymorphism

Answer 1

Option A "Nonsense" is correct.

Any change in the nucleotide sequences either by mistake when they are copied or due to environmental factors is called a mutation. Amorph is the result of mutation which causes a complete loss of function and mutated gene lost the ability to encode a functional wild-type protein or any new protein. The nonsense mutations are most likely to cause amorph because the nonsense mutation is point mutation (single nucleotide change in DNA ) which is responsible for conversion of a sense codon (codes for amino acids) into a stop codon ( amino acids codon which is responsible for the termination of protein synthesis). This results in incomplete/truncated or fully nonfunctional protein product.

Other options are not right because missense-nonsynonymous is a point mutation that arises as a result of single nucleotide substitution and causes changes in amino acids codon. As a result, a new protein product is formed. Sometimes nucleotide change in the DNA sequence did not cause any change in the encoded protein that is because of the degeneracy of amino acid codon ( because the changed codon also codes for the same amino acid), such mutations are known as missense synonymous mutation. Silent mutations are those mutations that did not affect overall protein function and phenotype. Polymorphism is the presence of a different form of the phenotype of a gene. Polymorphism is the result of mutations and natural selection. So, apart from nonsense mutation, other mutations did not give nonfunctional protein product, therefore option "A" is correct.