Hello Sravani Ponnam

Similarity between spontaneous and induced mutations include:

Spontaneous and induced mutations are the two types that bring about structural changes in DNA. Moreover, they both are heritable. Also, both these types of mutations are important in the study of functional genomics to find out the function of a particular gene in the genome.

On the other hand, difference between spontaneous and induced mutations include:

Their origin. Induced mutations occur due to mutagens from the environment while the spontaneous mutations occur due to natural causes.

The mechanism involved could also be one of the differences between induced and spontaneous mutations. Induced mutations occur due to the incorporation of base analogs, base mispairing, and base damage while spontaneous mutations occur due to the errors in DNA replication, spontaneous lesions like depurination and deamination, and transposable genetic elements.

In functional genomics, induced mutations are important in reverse genetics while spontaneous mutations are important in forward genetics.

Best.

Both spontaneous mutation and genetic engineering leads to heritable changes in the individuals. Whereas most spontaneous mutations are random and often deleterious, genetic engineering is targeted towards a specific direction, and the expected result is desirable.

The molecular basis of mutation relates to mis-pairing between nucleotides of the DNA molecule irrespective of whether the mutation is natural or artificial. However, classical genetic engineering aims at creating heritable changes by inserting a transgene into the genome of the recipient individual. However, the present day gene editing that includes addition, deletion or substitution of one or a few nucleotides is also included in genetic engineering. For details, you can access:

https://www.researchgate.net/publication/256293644_glossary_of_plant_breeding

Spontaneous mutations

So called „spontaneous mutations” in DNA may occur apparently randomly. In these cases, we cannot recognize the hidden cause of changes in DNA structure. First: Spontaneous mutations may result in serious inheritable genetic diseases when they are unrepaired. Second: spontaneous mutations may increase the inclination to specific diseases, including cancer, while certain genetic mechanisms are capable of counteraction ensuring more or less DNA stabilization. Third: randomly developing mutations may forward the genomic functions helping the healthy survival of individuals and progress of evolution. Fourth: Indifferent spontaneous mutation does not disturb health maintenance and survival of the individual.

BRCA1/2 gene mutation is an example for second type of spontaneous mutations. BRCA mutation carriers have specially increased inclination to breast and ovarian cancers. In the background, estrogen receptors (ERs) have weak capacity for liganded activation. In the DNA stabilizer circuit, mutant BRCA gene increases aromatase expression and activity, resulting in abundant estrogen synthesis and increased liganded activation of ERs. In BRCA mutation carrier women, anovulatory infertility is regularly associated with compensatory increased estrogen levels. Prevention of breast cancer in BRCA mutation carriers is not mastectomy and ovariectomy, but rather, increasing the liganded activation of ERs (Suba Z. 2015).

Induced mutations

Induced mutations caused by environmental factors or medical influences may serve the defense of health and survival of individuals. There is a good example of Asian mutation in hemoglobin protecting against malaria.(Asian Mutation Protects Against Malaria | Science | AAAS).

Induced gene mutations occur in tumors, when environmental endocrine disruptors or medical influences endanger even the remnants of DNA repair mechanisms. In tumor cells, an extreme estrogen loss via exhaustive aromatase inhibitor treatment induces acquired mutation in the ligand binding domain of ERs enabling them to accept growth factor receptor activation in an estrogen free milieu (Pejerrey SM, 2018). In tumors, growth factor activation of ERs is not a proliferative stimulus, but rather an effort for DNA repair and consequential apoptotic death Suba Z. 2020).