Navigating the World of Genetics: Key Terms
Understanding key genetics terms helps you make the most of your SelfDecode results. Here's a guide to foundational concepts that you'll encounter in your DNA reports. For more in-depth definitions, see the SelfDecode Glossary.
Understanding DNA and Your Genetic Blueprint
DNA
DNA (Deoxyribonucleic Acid) is the molecule that contains instructions for how your body grows, develops, and functions. It forms a twisted ladder shape called a double helix.
- The four bases in DNA: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C)
- Base pairing follows strict rules: A always pairs with T, and G always pairs with C
Genome
Your genome is your complete set of DNA—all your genes and the non-coding regions between them. You have about 20,000–25,000 genes, plus millions of genetic variants (differences) that make you unique.
- Variants include SNPs (single nucleotide polymorphisms), insertions, deletions, and structural variations
- Genes code for proteins; variants are differences that can influence how genes work
Allele
An allele is one version of a gene. You inherit one allele from each parent, and different alleles can lead to different traits.
Genotype
Your genotype is the specific combination of alleles you have for a particular gene. For example:
- AA — may increase a certain trait
- AG — moderate effect
- GG — may decrease the trait
Homozygous vs. Heterozygous
- Homozygous: Two identical alleles (AA or GG)
- Heterozygous: Two different alleles (AG)
How Your Genes Work
Gene Expression
Gene expression describes how your genes are turned "on" and "off" to make proteins. Not all genes are active all the time—your body controls which genes are expressed based on your needs.
Genetic Imputation
Imputation uses advanced statistical methods to predict genetic variants that weren't directly tested on your DNA kit. It fills gaps in your data by comparing your results to reference populations, making your genetic insights more complete and accurate.
Polygenic Risk Score (PRS)
A PRS combines the effects of many genetic variants to estimate your genetic influence on a trait or health condition. Unlike single-gene traits, most traits (like height or heart disease risk) are influenced by hundreds or thousands of genes working together.
Key Variants and Identifiers
SNP (Single Nucleotide Polymorphism)
- SNP: A variation at a single DNA position (the most common type of genetic variation)
- rsID: A unique identifier for each SNP (for example, rs4988235 is linked to lactose intolerance)
Why These Terms Matter
Understanding DNA, alleles, genotypes, gene expression, imputation, and polygenic risk scores gives you the foundation to explore how your genes influence your traits, health, and individuality.
Need personalized guidance on your results? Try Decody, our AI health coach, or speak with a healthcare professional or SelfDecode practitioner for one-on-one support.
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