What if I say that you looks like a mouse? Surely whosoever standing before me gonna shout on me or maybe punch me hard. But we (humans) are 75% similar to mouse. Now that’s Strange!. But you don’t need to look like a mouse for proving that 75% similarity. There are various other things in our body where we can see that similarity for example : genes.

Genie of Life

Have you ever wonder what special thing present in all top class athletes which makes them most popular among all of us. Do they born with special powers? Scientist have found out that these athletes have something common in them. What special thing they have? So that special thing which they have and also present in all of us is “Gene”.

Gene

Gene is like a blueprint of our body. It is the basic physical and functional unit of heredity which we get half from father and half from mother. Genes, which are made up of DNA, act as instructions to make molecules called proteins. The Human Genome Project has estimated that humans have between 20,000 and 25,000 genes. These Genes present in cells.

Genes in cell

Every human being has cell in it and it is estimated that single human being may contain 75 to 100 trillion cells in it. Inside cell the is nucleus within each nucleus we have “X” shaped structured called chromosome. There are 46 chromosomes 23 from father and 23 from mother. And within that chromosomes we have bundled called Gene or DNA.

DNA

DNA stands for deoxyribonucleic acid. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria. The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). DNA bases pair up with each other, A with T and C with G, to form units called base pairs. In real-time there are about 4-5 million bases in single DNA sequence. Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. DNA is just the basic structure it dose not tell us what to do. Like I want to shake my hand, want to jump etc. are not tell by DNA. Actual functions are performed by something we called Protein. Building block of proteins are called Amino Acids. So which amino acid will be formed with which base can seen Codon table.

I wrote above that “more than 99 percent of those bases are the same in all people” what does that mean?

When the cell is getting manufactured then the DNA get copied. During that replication a minor change in DNA will change whole structure of body. Lets take an example we know there are 4 bases in DNA: A, T, C, G and A paired with T and C with G. With these bases combination amino acid produce eg: ATG pair will produce “Methionine acid”. Take A, T and G bases for our example. Now suppose cell start replicating during first copy combination is ATG which is “Methionine acid”. During second copy it’s same ATG i.e “Methionine acid” but during third replication the middle T changed into G so it become AGG which is “Arginine acid”. With single change in base will change whole amino acid. So we are 99 % similar but that one sequence replacement can me us small or tall, guy with brown hair or black hair. This we called it as SNP’s (single nucleotide polymorphism)

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