Genetic Tests for Professionals: Basic Concepts
1/3/25
✍🏼 Marta Alonso
Genetics is the science that studies DNA, the instruction manual that defines much of who we are. This biological code not only determines visible characteristics like eye color or height but also invisible aspects such as how we metabolize food, react to certain medications, or even our predisposition to diseases. In the world of health and nutrition, knowing our genetics can be a powerful tool to improve our quality of life.
What are Genetic Variants?
The DNA of each person is unique, but shares more than 99% of its information with that of any other human being. What differentiates us are small variations in the sequence of our DNA called genetic variants. These variants, also known as single nucleotide polymorphisms (SNPs), are responsible for our unique responses to foods, physical activities, and medical treatments.
For example, some people have variants that make them metabolize caffeine faster, while others may experience longer-lasting effects. Similarly, certain variants may predispose to food intolerances, such as lactose or celiac disease. These genetic differences are what make a one-size-fits-all approach ineffective for everyone when it comes to health and nutrition.
Key Concepts in Genetics
To better understand the results of a genetic test, it is helpful to know some essential terms:
DNA (Deoxyribonucleic Acid):
Molecule that contains the genetic information of an organism, organized into genes that code for proteins or regulate biological processes.Gene:
Segment of DNA that contains specific instructions to produce a protein or perform a function in the organism.Chromosome:
Organized structure of DNA and associated proteins that contains genes. Humans have 23 pairs of chromosomes.Genotype:
Set of genetic variants of an individual in a gene or across their genome.Phenotype:
Observable manifestation of an individual's characteristics, influenced by their genotype and the environment.Homozygous:
Individual who has two identical copies of an allele at a specific locus of the genome.Heterozygous:
Individual who has two different copies of an allele at a specific locus.Allele:
Each variant of a gene at a locus (a defined position in the genome). For example, the eye color gene can have alleles for brown or blue eyes.Dominant Allele:
Allele that is expressed in the phenotype when present, even if there is only one copy.Recessive Allele:
Allele that is only expressed in the phenotype when an individual has two copies of it.Haplotype:
Set of genetic variants that tend to be inherited together due to their proximity on a chromosome.Gene Expression:
Process by which the information of a gene is used to produce a functional protein or RNA.Effect Allele:
Genetic variant that significantly influences a trait or disease.Trait:
Any observable or measurable characteristic of an organism, such as hair color or blood pressure.Monogenic Trait:
Trait or characteristic determined by a single gene, such as cystic fibrosis.Polygenic Trait:
Trait or characteristic determined by multiple genes, such as height or diabetes risk.Heritability:
Proportion of the variation in a trait in a population that is attributed to inherited genetic factors. In other words, it is the percentage of how heritable a trait is.GWAS (Genome Wide Association Study):
Method to identify associations between specific genetic variants and traits or diseases in large populations.Genetic Imputation:
Technique to predict genetic variants not directly genotyped in an analysis, using genomic reference data.Exome:
Portion of the genome that contains all the protein-coding regions (exons). Represents about 1-2% of the total DNA.Array:
Technology used to genotype thousands or millions of genetic variants simultaneously. It is common in large-scale genotyping studies.Structural Variation:
Alteration in the structure of DNA, such as duplications, deletions, or inversions of genomic segments.Epigenetics:
Study of changes in gene expression that do not involve alterations in the DNA sequence, such as DNA methylation or histone modifications.De Novo Mutation:
Genetic variation that appears for the first time in an individual and is not inherited from the parents.
The Importance of Knowing Genetics
A genetic test analyzes genetic variants related to different aspects of health, such as how we process nutrients, the predisposition to diseases, or how we respond to medications. These results allow for the personalization of professional recommendations to optimize patient health. Why is it important? Here are some key benefits:
Personalization of treatment: Genetics influences how a person responds to medications, treatments, and dietary recommendations in a unique way.
Identification of risks and prevention: Genetic analysis can reveal predispositions to certain diseases, such as diabetes, hypertension, or cardiovascular diseases.
More accurate diagnoses: In some cases, the symptoms of one disease may be similar to those of another, but genetic analysis can provide clarity. For example, in disorders like lactose intolerance or celiac disease, genetic tests complement clinical tests.
Optimization of performance and well-being: In areas such as sports nutrition, genetics can help identify the types of exercises or nutrients most effective for improving physical performance and recovery.
Improved patient adherence: When recommendations are backed by genetics, patients tend to be more motivated to follow them.