12 HEALTH & WEALTH MANUAL “Nourishing Human Potential”
A Quick Genetics Tutorial
Within every human cell is an individual’s blueprint for life —
their DNA. DNA contains the master information that is needed
to construct and maintain the human body.
DNA is long. About six feet long, to be exact, if you took the DNA contained within one cell and stretched it end to end.
There are several different ways that these long strands of DNA can be divided into smaller pieces.
The largest unit of DNA is a chromosome. There are 23 pairs of chromosomes
inside of our cells: one set from each parent. These 23 pairs contain all of our
The next unit down is a gene, which is simply a sequence of DNA that
corresponds to a particular inheritable trait. There is a gene for hair color, for
example, and a gene for height. We get one gene from each parent for each
inheritable trait. These are called alleles.
The main job of each gene is to encode — or tell the body how to build —
different proteins. While that may seem like a small job, proteins serve many
critical functions in the body. Enzymes, for example, are proteins.
The smallest unit is a nucleotide, which is the “building block” of DNA.
Nucleotides are tiny: less than one millionth of a millimeter!
Small Changes in DNA that Impact Our Physiology
On a strictly DNA basis, humans are surprisingly alike. Despite our apparent differences,
the DNA between any two people is 99.1% identical. That 0.9% variation in DNA,
however, is hugely important, accounting for all of our genetic differences.
Small variations in DNA are called polymorphisms. Blood type is a common human
polymorphism. Depending on the order in which the nucleotides in your DNA line up,
you could have blood type A, B, A/B, or O. Some polymorphisms are so small, they
affect the order of just one pair of nucleotides. These are called single nucleotide