HSA | FSA CARDS ARE NOW ACCEPTED

Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on peptides and GLP-1. Browse all Peptides & GLP-1 education

Most genetic test reports use terms that most readers have never been taught. SNP. Allele. Genotype. Variant. Pathway. The words appear in results, in research papers, and across the precision health category — but they're rarely defined well, and when they are, the definitions tend to generate more questions than they answer. The Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, and 150+ genetic insights, producing a report that uses all of these terms in specific, technical ways. This guide defines each one in plain English — so that when your report says "FTO rs9939609 AA genotype" or "COMT Val158Met variant affects the methylation pathway," you know exactly what that sentence means.

The Foundation: DNA, Chromosomes, and Code

Before the terminology, a foundation. Your genome is approximately three billion base pairs of DNA — a code written in four letters: A, T, G, and C. DNA is organized into chromosomes (23 pairs), and within chromosomes, specific segments encode instructions for building proteins and regulating biological processes. Genetic testing reads specific positions in that code to identify where your sequence differs from a reference and what those differences mean for how your biology operates.

What Is a Gene?

A gene is a defined segment of DNA that encodes a specific protein or performs a specific regulatory function. Genes are the named units of genetic testing: FOXO3, COMT, ACTN3, FTO, SHBG. Each gene encodes a specific protein with a specific biological role — ACTN3 encodes alpha-actinin-3, the structural protein in fast-twitch muscle fibers; COMT encodes catechol-O-methyltransferase, the enzyme that methylates catechol estrogens. When a gene name appears in your results, it tells you which protein-encoding unit the relevant variant sits within or near. The Precision Peptide Genetic Test analyzes variants across 48 genes.

What Is a SNP?

A SNP (single nucleotide polymorphism, pronounced "snip") is a specific position in the genome where the DNA base varies between individuals. At most positions, everyone carries the same base. At SNP positions, some people carry one base (A) while others carry a different base (G). SNPs are the primary unit of variation analyzed in genetic testing because they're common, stable across a lifetime, and have documented associations with biological traits and pathways. FTO rs9939609 is a SNP — "rs9939609" is its unique reference number in the global SNP database. The Precision Peptide Genetic Test analyzes 57 SNPs, each selected for its research-backed relevance to peptide-related biological pathways.

What Is an Allele?

An allele is one specific version of the base at a SNP position. Since you inherit one chromosome from each parent, you carry two alleles at every SNP — one maternal, one paternal. At FTO rs9939609, the possible alleles are A and G. You carry some combination of the two: AA, AG, or GG. At COMT Val158Met, the alleles are named for the amino acid they produce at position 158 of the COMT protein — valine (Val) or methionine (Met). The specific combination of two alleles you carry at a SNP position is your genotype.

What Is a Genotype?

A genotype is your complete allele combination at a given SNP position. For FTO rs9939609, the three possible genotypes are AA, AG, and GG. For COMT Val158Met, they're Val/Val, Val/Met, and Met/Met. Some genes use presence/absence notation instead — the GSTM1 null genotype means both copies of the gene are deleted, producing no functional enzyme activity. Whatever the notation convention, a genotype describes which allele pair you carry — and genotype is the level at which the Precision Peptide Genetic Test generates insights about your biology.

What Is a Variant?

The word "variant" is used broadly in genetic reporting to describe a specific genotype at a specific SNP that differs from a reference baseline. "The ACTN3 R577X variant" describes the specific SNP at position 577 of ACTN3 where arginine (R) or a stop codon (X) can appear. "The FTO rs9939609 AA variant" means the AA genotype at that SNP. In the Precision Peptide Genetic Test, variants are classified by their research-backed associations with biological pathways — not by clinical disease categories — which keeps every insight in the appropriate wellness and educational framing.

What Is a Pathway?

A pathway is a network of biologically related genes, proteins, and molecular processes that collectively regulate a specific biological function. Longevity isn't one gene — it's a pathway: FOXO3 regulates cellular stress response, SOD2 handles mitochondrial antioxidant defense, APOE shapes lipid transport and cognitive aging, SIRT1 drives sirtuin-mediated DNA repair, TERT maintains telomere integrity. Weight management isn't one gene — it's a pathway: FTO drives appetite regulation, MC4R governs satiety signaling, TCF7L2 shapes glucose metabolism. The Precision Peptide Genetic Test organizes 150+ insights into 14 pathways because no single gene tells a complete biological story. Pathways reveal how your variants interact as a system.

How These Terms Work Together in Your Report

When your results say "COMT Val158Met — Met/Met genotype — slow methylation tendency in the estrogen clearance pathway," every word carries a specific meaning. COMT is the gene. Val158Met is the SNP (the position in COMT protein where valine or methionine appears). Met/Met is your genotype — two methionine alleles, the slower-acting combination. "Slow methylation tendency" is the pathway-level interpretation: what that genotype means for estrogen clearance biology. Each insight in your report follows this structure: gene → SNP → genotype → pathway interpretation. For a step-by-step walkthrough of how to navigate the full report, see our guide to reading your Precision Peptide Genetic Test results.

Genetics as a Guide, Not a Guarantee

A Met/Met COMT genotype doesn't diagnose any condition — it reveals a methylation tendency worth discussing with a qualified healthcare provider. An AA FTO genotype doesn't determine your weight — it reveals an appetite and satiety architecture that responds to specific interventions. Variants are tendencies, not destinies. Understanding the terminology is the first step; using it to have better-informed conversations about your biology is the payoff. For the full overview of what the Precision Peptide Genetic Test measures and how the 14 pathways connect, see our guide to genetic peptide testing. That's what testing before you invest actually delivers: precision, not prediction.

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use. Consult a qualified healthcare provider before beginning any peptide protocol.

Ready to understand what your genes say about your peptide response? Take the Precision Peptide Genetic Test

Frequently Asked Questions

What is a SNP in genetics?

A SNP (single nucleotide polymorphism) is a genome position where the DNA base varies between individuals. Some people carry an A at FTO rs9939609; others carry a G. SNPs are the primary unit of variation in genetic testing. The Precision Peptide Genetic Test analyzes 57 SNPs across 48 genes, delivering 150+ insights across 14 pathways.

What is the difference between a gene, a SNP, and a variant?

A gene encodes a protein — FOXO3, COMT, ACTN3. A SNP is a variable position within or near a gene — FTO rs9939609. A variant is the specific genotype you carry at that SNP — FTO rs9939609 AA. The Precision Peptide Genetic Test analyzes 57 SNPs across 48 genes and reports 150+ variants.

What is a genetic pathway in peptide testing?

A genetic pathway is a network of related genes and processes that collectively regulate a biological function — longevity, weight management, muscle growth. The Precision Peptide Genetic Test organizes 150+ insights into 14 pathways because no single gene tells a complete story. Pathways reveal how your variants interact as a biological system.

This article is part of the PlexusDx Education Hub. Browse all Peptides & GLP-1 education

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.