Eli5 what makes everyones dna unique and how can we see that under the microscopen?

Question

I was wondering how each dna off someone is unique to another and how we can see those changes.

In: 5

Answer 1

DNA between humans is about 50% similar to that of plants and animals in general. We’re 80% identical to cows and about 90% similar to felines!

Humans are probably 99.9%+ similar to each other with a genome length of ~3.2 billion bases (each of those locations is a nucleobase either A, T, G or C). Each cell’s DNA is spaced into 46 chormosomes (23 pairs – each being a large blocks of DNA).

There is a technology called gene sequencing, where the order of each of these blocks can be read out (1st position is A T, G or C, – 2nd position is? etc). There are MANY ways that one can do this, but more modern versions use lasers and electrical currents to quickly record which base is present at either position.

Older methods (sanger sequencing) would take a piece of DNA and chemically break it into parts, separate them, and you could use the output of the experiment to effectively identify the sequence like putting together a puzzle.