Genetics is defined as “the study of heredity and the variation of inherited characteristics” while Genomics is “the branch of molecular biology concerned with the structure, function, evolution, and mapping of genomes.” As genetic technology continues to evolve, we are gaining more and more understanding of our chemical programming.
Most humans have 23 sets of paired Chromosomes, each with a lengthy list of instructions to produce other chemicals for the body. I say “most humans” because there are a few variations, mostly due to missing or broken Chromosomes. Each Chromosome contains between 25 and 125 million pairs, with a total of approximately 3.3 billion pairs in each of our cells. With the exception of Red Blood Corpuscles, this overwhelming recipe is repeated in each cell of our bodies.
Within the Chromosomes are Genes, related sets of pairs that provide instructions for various parts of the body. There are Genes for eye color, hair color, skin color, height, muscle development, digestive function, etc. A Gene could be just one base pair or several dozen, depending on the complexity of the function it controls.
Each pair is made from two pieces of genetic material called Nucleotides commonly known as A, C, G, or T (Adenine, Cytosine, Guanine, and Thymine). When replicating, each Chromosomes “unzips” and allows enzymes to make copies of the genetic material. There are times when an incorrect copy is generated, which would be a mutation or variation. These variations are referred to as Single-Nucleotide Polymorphisms (or SNPs).
In recent years, genetic scientists have completed mapping the Human Genome, and there are a few available databases sharing their data. One of these sites (SNPedia.com) has allowed me to look up my particular pairs in my genome to compare with others. There are approximately 1.5 million SNPs identified in the Human Genome (much of our genetic material is not yet decoded or serves no obvious purpose). Specific pairs are indicated by “rsID” (e.g., rs123456), which is an abbreviation of “Reference SNP cluster ID.”
One example is rs5215. It is on Chromosome 11 and is in the KCNJ11 Gene (part of the Glucose metabolism system). The benign, standard nucleotide is ‘C’ and the variant is ‘T’ and most healthy people have the pairing C-C or C-T. However, my pairing is T-T, making me more susceptible to Type 2 Diabetes.
Another noteworthy set is rs4149056 and rs4363657 from the SLCO1B1 Gene (it produces an protein that assists bringing certain substances into the Liver). Here, the benign, standard nucleotide is ‘T’; the ‘C’ variant decreases the effectiveness of the transport protein, preventing Statin medications from entering the Liver (I mentioned my issue with Statins in an earlier post) and leads to increased muscle pain as a side effect. My genome has ‘C’ nucleotides in all four positions. This explains why I have such a difficult time with Statin medications.
Two of my relatives (a male First Cousin and my Mother’s Brother) also had genetic testing, and they have given me permission to examine their results. This has allowed me to compare my Genes with theirs to determine from which side of my family I inherited certain traits.
I have an appointment with the UCSF Genetics Clinic and I will wait to hear their results before I write anything more here. Back soon with lots of new stuff!