What if we always showed each other respect
and tolerated our few differences?
All people are 99.9% alike genetically. Along with our environment, experiences and culture, the remaining 0.1% genetic difference accounts for the uniqueness of each one of us. We ask you to tolerate one another’s few differences because of the overwhelming similarities we share.
What is meant by the statement, all people are 99.9% alike genetically? The answer comes with a basic understanding of genes and DNA
You are born with a unique body
It comes with its own operating instructions – one half from your mother and the other from your father. Unless you have an identical twin, no one has the exact same operating manual that you received.
You begin life as a single cell. This cell divides and takes on different forms, until there are over 30 trillion cells that make up your body. Each one of these cells is about 10 to 100 micrometres in diameter – the width of a human hair. Yet each cell (except for red blood cells) contains a copy of your body’s full operating manual. Each instruction in your operating manual is called a gene.
Collectively, your genes are known as a genome. Your genome contains about 20 000 genes, each of which contains instructions for building different proteins. Your body’s functions rely on proteins. With such a large number of genes, it is easy to understand why you are unique.
Each gene is responsible for manufacturing a particular protein or set of related proteins. Just like letters of the alphabet make up certain words, the sequence of the four nitrogen bases in a gene determines the exact structure of each protein.
Your entire genome is made of DNA that is 3.2 billion nitrogen bases long. If this DNA was removed from a cell and uncoiled, it would measure two metres long. These two metres of DNA contain the complete chemical instructions for building and operating your body.
Your genome determines your skin, hair and eye colour. Along with your environment, including diet and exercise, your genome also determines how tall you are, how coordinated you are on a sports field, and whether you are at a higher or lower risk of disease – like having a heart attack or getting cancer.
While your genome gives you the ability to understand language and to wonder, the particular language you speak and the beliefs you have are determined only by your environment and upbringing.
When you think about your many cultural traits and your thousands of genetic traits, you realise that no person has ever been – or will ever be – exactly like you. You are unique.
Your genetic uniqueness is due to variants in the sequences of nitrogen bases in the genes that determine your unique characteristics. Many of these variants arose through mutations in the genes you inherited.
Underlying your uniqueness are an overwhelming number of similarities you share with other people. Your eye colours may differ, but you have two eyes. Each eye has a lens, a cornea, an iris, and a retina – all of which function in much the same way. You may be shorter or taller, but we all have legs, arms and the same bones that make up your skeletons.
All of the similarities between you and other people exist because you share the same genes with the same nitrogen base sequences for those characteristics.
In fact, the sequence of the 3.2 billion nitrogen bases in your entire genome is 99.9% identical to the sequences in any other person – no matter where the two of you come from.
Chromosomes can be seen under a microscope to be X-shaped structures found in the nucleus of each cell. They contain your genes.
Each gene is made of deoxyribonucleic acid (DNA).
When you take a closer look, each DNA molecule consists of two long strings of smaller chemical building blocks. These are called nucleotides.
The two strings are linked by pairs of nitrogen bases, one from each nucleotide, and are coiled into a twisted ladder shape called a double helix. There are four different nitrogen bases in DNA: adenine always pairs with thymine (shown as blue and pink bars); and cytosine always pairs with guanine (shown as red and orange bars).