What are mutations?

Mutations refer to random errors that occur during the process of gene replication. These changes can happen due to mistakes made by DNA polymerase while copying the DNA, or they may be induced by external factors such as radiation or chemicals. As a result, mutations can lead to alterations in the nucleotide sequence of a gene, which may affect the protein produced or have no effect at all.

Mutations are an important source of genetic diversity within populations, as they introduce new alleles into a gene pool, which can be acted upon by natural selection. Some mutations may lead to beneficial traits, while others may be neutral or harmful.

In contrast, planned genetic alterations and intentional changes in DNA suggest a level of control and design that does not reflect the random nature of mutations. Infections causing genetic change may refer to viral integration into the host genome but do not align with the general definition of mutations, which are primarily spontaneous or result from copying errors. Thus, the nature of mutations as random errors in gene replication is what makes the correct answer stand out.