if all the genes in our body are the same how come we have so many different cell types that perform different functions?

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if all the genes in our body are the same how come we have so many different cell types that perform different functions?

In: Biology

Basically the different cells only use the parts of the DNA that they need. Genes that aren’t used by a particular cell are essentially turned off so they aren’t used to assemble proteins.

Not all genes are used in every cell.

Imagine I gave 3 people a general housekeeping book (this is DNA in my metaphore) which contains: recipes, cleaning tips and, sewing instructions etc.

Then I asked one person to bake a cake, one person to do laundry and one person to re-sew a button onto a shirt using the info in the book.

They all have the same total information, but they look at different parts of the book for instructions.

The DNA in our cells contains the blueprints for many different cells, but only some of the instructions are “expressed” at any given time. The mechanisms for this are extremely complex but by the expression of certain genes different cells and organs are grown from the same master instructions.

It’s called epigenetics!
Your genes are made of DNA. Your DNA is shaped like a really long strand, but it’s coiled *real* tight. Because of this coiling, only some parts of the DNA are turned outwards, and are thus able to tell the cells what to do.
There are chemicals that affect how your DNA coils, and which bits are facing outward – and so change how the cell behaves, what it looks like, what it does, and so on.
It’s like a manual, where you’re only allowed to read the open page – but different things tend to leaf through and leave different pages open. Sometimes, it’s page 2 and 3, and sometimes is page 46 and 47.

Epigenetic changes can also come about because of your hormones, lifestyle, food, activity, environment, and many other things.