“Nothing occurs, either in the Earth or in yourselves, that was not set down in writing before We brought it into being–that is easy for Allah” (Quran, Al Hadid, 57: 22)
DNA or your genomes, have all the information your body needs to function, make more cells and each cell knows, because of Methyl groups, what cell function to manifest. The Methyl group switches on and off the Genome. Histones, which are proteins, are more like knobs then switches. They control how much each gene is expressed, depending on how tightly wound the Histone allows. So the Genome (DNA) is the hardware, and the epigenome is like the software, telling the DNA what to do. Each of our tendencies is imprinted on our genetic code and can be passed down to our children.
Imagine we have some twins, like the pair opposite, they were separated at birth and have the same genetic code. They ended up following very different lifestyles and as a consequence, twin one has a different gene code operating than his twin brother. Why is that? In the science of Epigenetics (literally above genetics), we find the different gene codes become activated or recessed according to lifestyle choice and external factors. The decisions we take and the actions we do can literally change our genetic code. Studies have shown for instance that when the protective chemical that seals the gene becomes frayed due to stress and anxiety, the gene stops producing a healing code and a person may develop serious illnesses like cancer and mental disorders. If, on the other hand, people adopt a healthier and more positive lifestyle, then their genes become more effective and they are much less likely to get a serious disease, even if it is in their genetic code. So is our destiny fixed? Perhaps our potential destinies are all written into our DNA code “…set down in writing.”(57:22), but with the gift of free will, we can either become our best or worst versions of ourselves!
Allah’s Messenger (ﷺ), the truthful and truly-inspired, said,
“Each one of you collected in the womb of his mother for forty days, and then turns into a clot for an equal period (of forty days) and turns into a piece of flesh for a similar period (of forty days) and then Allah sends an angel and orders him to write four things, i.e., his provision, his age, and whether he will be of the wretched or the blessed (in the Hereafter). Then the soul is breathed into him. And by Allah, a person among you (or a man) may do deeds of the people of the Fire till there is only a cubit or an arm-breadth distance between him and the Fire, but then that writing (which Allah has ordered the angel to write) precedes, and he does the deeds of the people of Paradise and enters it; and a man may do the deeds of the people of Paradise till there is only a cubit or two between him and Paradise, and then that writing precedes and he does the deeds of the people of the Fire and enters it.”
Watson, Yasmin; Val Baker, Dr. Amira. Science in the Qur’an – A Young Person’s Guide: Discovering Scientific Secrets in the Holy Qur’an (Page 39). . Kindle Edition.
Sahih Bukhari 6594: Book 82, Hadith 1, Vol. 8 Book 77, Hadith 593. https://sunnah.com/bukhari/82/1