DNA Explained in 5 Minutes
The DNA sequencing industry is developing at lightning speed. It's poised to bring massive change.
But what's DNA anyway?
It's a molecule.
But not just any molecule.. the human DNA molecule is about 1.5 meters long and incredibly thin.
The shape of the molecule is very clever. Think of a ladder with 4 different color rungs. The sequence of colors is the information!
Now imagine a ladder with about 3 billion rungs and with an amazing twist. Literally. Nature twists the molecule into a corkscrew (helix) shape. This simply gives it extra strength, because a break in the DNA molecule would have disastrous consequences.
That's the amazing human DNA molecule!
Nature takes very good care of the huge DNA molecule - it winds it up and packs it into separate containers called Chromosomes. This is just an efficient method to make sure the molecule fits into a tiny space and is protected.
The whole packaging system, with the DNA molecule wound and packed into Chromosomes, is referred to as a Genome. But it's just a molecule!
The DNA molecule encodes data that acts as a program to run each cell in the body. Just like computer data can be reduced to strings of 0s and 1s (2 units), DNA uses 4 units.
The order (sequence) of these units is the program.
And Nature is massively parallel. No central processor here.. every cell in the body contains a copy of the DNA molecule.
Think of a cell as a factory. It manufactures all sorts of substances, and the instruction on how to do this is provided by the DNA. Many of these substances are proteins, so DNA has special instruction sequences (called Genes) that tell exactly how to make different proteins. The sections of DNA between the Genes are a bit of a mystery. It's not clear exactly what these instructions do, if anything.
So the cell simply reads the DNA instructions and makes the appropriate proteins. It's a wonder of molecular manufacturing!
DNA can be analyzed at many levels, for example..
- Just look at the chromosomes for abnormal shape.
- Sequence (read the order of the units) a gene in one of the chromosomes.
- Sequence all genes in one of the chromosomes.
- Sequence all genes in all the chromosomes.
- Sequence all the DNA (even the instructions between the genes) in all the chromosomes. This is called "full sequencing".
A major producer of DNA sequencing machines is a company called Illumina. They reduced the cost to sequence a human DNA molecule from $100 million in 2001 to about $1,000 in 2014. The rate of progress is staggering!
Do we all have the same exact DNA?
No. We are all 99.9% the same, but that 0.1% means about three million differences between your DNA and anyone else's. It's these differences that are used in DNA testing.
Oh, and our DNA is about 99% the same as our closest relative, the chimpanzee.
Content written and posted by Ken Abbott firstname.lastname@example.org