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Personal Genetics: DNA, SNPs, GWAs, and Haplotypes

Everyday Einstein explains the different elements of our genetic make-up. How do they work together to determine our traits? Click to find out. 

By
Lee Falin, PhD,
Episode #126

Chances are, you or someone you know has had their genome analyzed by one of the many personal genome testing services. You probably also heard that the FDA recently ordered that one of those companies, 23 and Me, stop providing health reports for those tests due to some issues they had with the way those results were presented.

Whether you think the FDA was right or wrong about this, let’s take a look at what kind of information goes into these tests, and what you can and can’t learn from them..

DNA 101

As I’ve mentioned on several past episodes, the genetic information you have comes from two sources, your mother and father. For the majority of people, every cell in your body has 23 pairs of chromosomes. One set comes from your mother, and one from your father.

Each of those chromosomes is a very long string of DNA made up of four different types of molecules called nucleotides. Those nucleotides are Guanine, Cytosine, Thymine, and Adenine. Each chromosome has between 40 million and 250 million of these nucleotides.

When we talk about a DNA sequence, what we are usually referring to is a long list of letters that represent that long list of nucleotides. Usually, the nucleotides are abbreviated to G, C, T, and A, respectively. 

By themselves, these nucleotides don’t really do anything. However they contain the instructions that tell your cell how to build proteins, RNA, and other molecules it needs to keep your body running smoothly. 

When genetic sequencing was first in its heyday, scientists believed that by looking at your genetic sequence, they would be able to figure out everything about you, from your eye color to your IQ to how likely you were to get a certain disease. Unfortunately, things turned out to be not quite that simple.....

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