[Petrochemicals (OP)]

Genetic science has figured aout a way to turn off genes so as to help people with  problematic genes with their condition. Can nature employ similar genetic affectation?

[alancalverd]

Eventually. It's called death. If your genes predispose you to serious illness, you are likely to get sick and die earlier than average, which reduces the probability of your passing those genes on to the next generation. 

[Kryptid]

The first example that came to my mind is lactase in most mammals. Lactase helps infants digest milk, but adults don't produce lactase. I would therefore infer that the gene that produces lactase is silenced during the adult phase of life.

[alancalverd]

That's particularly interesting in humans. It has been suggested that the evolution of  caucasians is associated with adult lactasia, which allowed some subspecies of homo sapiens to survive in northern Eurasia by milking other species in winter.

[chiralSPO]

Genetic science has figured aout a way to turn off genes so as to help people with  problematic genes with their condition. Can nature employ similar genetic affectation?

As I understand it, we learned this trick from nature. This subject is called "epigenetics."

Genes can be activated and deactivated, up-regulated, and down-regulated, through mechanisms such as DNA methylation and placement of histones.

see also:
https://en.wikipedia.org/wiki/Epigenetics
https://www.cdc.gov/genomics/disease/epigenetics.htm

[evan_au]

There are many "fossil" genes in the human genome which are no longer functional because of mutations.

One that springs to mind is vitamin C - most mammals can synthesize their own vitamin C, but humans and apes can't, so for us it becomes a vitamin, or "VITal AMINe". Since Vitamin C occurs in fruits, loss of this gene wouldn't be fatal in species which have a diet rich in fruit - unless members of those species go on long sea voyages, and the fruit rots. This led to the discovery of the disease scurvy.
https://en.wikipedia.org/wiki/Vitamin_C

There are several mechanisms that can lead to these "pseudogenes", including loss or insertion of a single DNA letter; this causes a "frame shift", which produces a nonsense protein.
https://en.wikipedia.org/wiki/Pseudogene