Epigenetic class 2: How epigenetic alteration helps us evolving and surviving in all condition?

How epigenetic alterations influence our life.

Image credit: www.davidebonazzi.com

Humans are originated from the African subcontinent and migrated all over the world. Epigenetic alterations make us adaptive in all conditions. Actually, migration, selection, genetic drift and mutation are the major forces which help us to evolve and survive.

Unfavourable conditions can create a mutation in our genome and mutation promotes origination of new allele in the population, but new allele may eliminate if the new allele is non-adaptive. Individual who has expressed a new allele, if he cannot survive in the population than the new allele is excluded from the population.

Epigenetic alterations are non-programmed, it can produce polymorphism depending upon the requirement. Whereas mutations are programmed, if a new mutation is helpful than it will be activated otherwise it will be eliminated.

Change in the expression pattern of a particular gene under the influence of epigenetic forces is called as an epigenetic alteration. Forces which leads to epigenetic alteration are methylation, Histone modification, chromatin remodelling and non-coding small RNAs. For more detail on epigenetic alteration click here.

Let us understand the mechanism by taking a simple example. A giraffe needed a long neck for eating leaves from a tree while a cat does not need it. The length of the neck is controlled by some gene, expression of that gene is highly regulated by epigenetic patterns (pattern of methylation) in both animals. But on the verge of evolution functional needs of giraffe, formulated a unique epigenetic pattern for its neck length gene and the gene is over-expressed, results in the long neck. 

For all the traits which are evolved today, is developed from the same mechanism. Another important role epigenome plays for us, is storing the changes.

Image credit: www.nestle.com.au

The newly emerged alteration, if it is useful than it is stored in the organism and pass on to the next generation. We have to understand,  that the long neck of the giraffe is not evolved overnight, it took thousands of year to evolve and develop a unique methylation pattern for expression of that particular gene for a long neck.

Epigenetic changes are inherited into offspring. If a father is suffering from some digestive track defect, of course, his epigenetic pattern is altered, and it will pass on to his child and so his child may suffer.

Remember each and everything what you eat, what you do, your routine, how you sleep, how you live and even how you think, create changes in your epigenetic profile.

Originally the mechanism was evolved for providing protection. It protects our genome from attacking by harmful transposable elements and microbial infection. Immediately, it methylates foreign DNA sequences and makes it inactive. For more detail understanding on different types of modification in epigenetic alteration click here.

Though epigenetic always do a favour in evolution, it has some vulnerable effects on genome. Sickle cell anemia in which red blood cells become sickle shaped, protect us from malaria infection because malaria parasite cannot recognize a sickle shape RBC.

Evolution is highly managed by epigenetic changes. Let’s understand it with another example, migration. Organisms have been transferred from one place to another place for a better life and survival. But they needed change, as Africa is a warm place if they migrated to Europe they needed a special mechanism which helps them to survive in the cold European climate.

This need was satisfied by epigenetic alterations. Some random mutations established new allele for survival and epigenetic alteration maintained expression of this new allele in that environment. 

Though epigenetic always did a favour in evolution, it has some vulnerable effects on our genome. Sickle cell anaemia in which red blood cells become sickle-shaped, protect us from malaria infection because malaria parasite cannot recognize a sickle shape RBC. in heterozygous condition sickle allele favours us but in homozygous dominant condition, it results in anaemic condition. 

Sickle allele evolved actually to helps those population, which was lived in high mosquito prone region of the world. The condition is autosomal recessive, it is totally safe and cannot cause any genetic defect. 

Over a period of time, it becomes vulnerable for the same population, in which it was helpful. The story is almost same for diabetes mellitus in the European population. Some harmful genetic conditions were actually useful in past.

We cannot predict how epigenetic alteration favours us, maybe it temporarily become vulnerable and helps in long-term survival or vice a verse.  Even if it is uncontrollable, we can somehow manage it by taking healthy actions.

If we take the proper diet, proper sleep, proper routine life, proper physical activity and proper medication, we can healthily execute our epigenetic profile for a longer period. Remember, if you are a smoker, maybe you will escape from cancer but your child cannot.

Image shows tightly packed and loosely packed transcriptionally inactive and transcriptionally active DNA region, respectively. Image credit: Image credit: www.janewhitney.com

What you damaged (damaging epigenetic profile) by smoking will pass on to your child and your child or his child or may be one of your generations will be suffered by cancer. Who knows, maybe your entire descent will extinct.

Personalised medication will be the next requirement for our endurance. The doctor will give you medication as per your genomes requirement. Some medicines produce an adverse effect on our health because our body cannot accept it.

This type of drugs always alters our genetic composition, especially epigenetic profile. It is always advisable to take medicines which are best suits you. Technologies are now very advanced, CHIP/CHIP and Chip on CHIP assays help you to know your epigenetic profile.

Now you can manage your epigenetic profile as like managing your monthly expenses. However, the technique is very costly but we hope that It will come under our pocket expenses in the future.

Like we adversely dominating our environment, one day it will become a reason for our extinction. In these conditions, it is necessary, that we store our genetic information and it will help us to improve the quality of our life, maybe in the future.

The moral of the story is, what we are today is due to millions of beneficial and non-beneficial alterations in past. Remember epigenome always gives the best version of us, by improving our survival potential and eliminating unhealthy, weak individuals because the ultimate goal of all the fundamental processes is “survival”.

Story written and covered by – Tushar Chauhan

Reviewed by – Ravi Parmar

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Story of DNA

Story of Protein

Story of Chromosome

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