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    GENETICS DEEP DIVE:

    Building on the basics

    Genetics is the study of genes and how they work. The study of genetics requires a microscopic look into a tiny, but complex part of your body: DNA. DNA can be found in the trillions of cells in your body, and your DNA possess all of the information that makes you who you are, from how you look to your risk for future health-related issues.

     

    Gene Strand

     

    All of that information is stored as four chemicals, known as bases, within your DNA:

    Adenine (A)

    Thymine (T)

    Cytosine (C)

    Guanine (G)

    These bases work together like the letters of an alphabet, and it's the sequence of these letters of your DNA that makes you, YOU!

    DNA is shaped like a twisted ladder, and each rung has a specific purpose. Rungs are made up of connected base pairs that store specific information about who you are.

    Changes in the order of these letters makes you different from other people (from physical characteristics, like your eye color to more complex ones, like how your body reacts to certain medications).

    All this DNA is organized within the chromosomes in our cells. We all have 23 pairs of chromosomes in (almost) every cell, and this is where all of our genes are located. For instance, genes for eye color can be found on chromosome 15.

    chromosomes

     

    Genes are sections of your DNA. Genes are made up of about 27,000 base pairs, or letters in your alphabet (A, T, C, G), on average. Humans all have the same number of genes (about 20,000), but what makes us unique is the variation within these genes (variations in your alphabet). The exact order of the As, Ts, Cs and Gs is important because this is the blueprint for making proteins, which are the building blocks of how the body works.

     

    If genes are the instructions, then proteins are the products built using those instructions. Think about it this way: you've just bought a new table that requires assembly. The instruction manual that comes with the table is your genes. It tells you how to put all the pieces together to build the table. Your cells read a gene to know how to build that specific "table" protein.

    Location, location, location. Within genes, bases vary from one person to another. We call these variations single nucleotide polymorphisms (SNPs). For a moment, let's take a look at one gene measured by Mindful DNA Professional and the Genecept Assay, the gene called MTHFR.

    This gene is important in controlling the activity of an important protein that activates folic acid. But a small change from a C to a T (a SNP), as you see below, changes the activity of this enzyme.

    So, who determines which alphabetic letters you have across 10 million SNPs? Your parents! For each gene, you have inherited one gene (called an allele) from your mother and one allele from your father. The combination of these two genes, which might have different SNPs, is called your genotype at a particular location in the genome. Going back to the MTHFR example, children can have one of three genotypes (at this particular location) depending on their parents' genotypes: C/C, C/T, or T/T.

    DNA2

    What genotypes actually tell us.

    Let's go back to the table we built earlier. Not only did it come with instructions, but it also came with all the components you needed to build the table. But before you received it, the table kit was made in a factory by workers who followed another set of instructions. That is exactly how our bodies work too! Some genes instruct our cells to build raw materials, and some genes instruct our cells to put those materials together.

    genotypes

    Let's assume for a moment that the table manufacturer offers 3 types of tables.

    All 3 tables may look different and even have different functions, but they all have the same kind of parts: 4 legs, 1 top, etc. In this example, the 3 different types of tables are just like the 3 genotypes, C/C = kitchen table, C/T = coffee table, T/T = bedside table.

    At the factory, the workers will build the parts following the manufacturing instructions. The instructions will be slightly different for each of the 3 tables resulting in tables with different leg lengths or top sizes. By making a small change to the manufacturing instructions, the workers produce different parts that will be assembled into different tables.

    If the order of letters in one of our genes has a small change (a SNP), the protein our cells make can be different as well. Depending on what you need to use the table for, one model may work better than others, or in some cases these changes don't matter at all. For example, if you need to eat dinner with your family, then the kitchen table will work better than the coffee table or bedside table would. If you need a place to put a glass of water, then all 3 tables work equally well.

    This is the same with SNPs. In some cases, changes in a gene order matter, and in other cases, the changes don't make any difference. In those instances when the changes in gene sequence (SNPs) do matter, we can sometimes use that information to help guide health decisions, like trying certain medications and other treatments that may work better for a particular person.

    About Genomind Professional PGx Express

    Genomind® Professional PGx ExpressTM is a test that looks at certain genes that may affect your body’s sensitivity or response to certain drugs and other treatments. Genomind Professional PGx Express is the leading test of its kind and looks at a group of key genes specific to mental health treatments. Your clinician can order this test for guidance that helps inform treatment decisions for you.