From Gene to Hereditary Trait

From Gene to Protein

The information carried by a gene doesn't stay abstract: it is used by the cell to build a protein, a molecule that performs a specific function in the organism (structure, transport, catalyzing reactions...). It is by producing different proteins, depending on which genes are activated, that the cells of a single organism specialize (muscle cell, skin cell...), even though they all carry the same DNA.

A Concrete Example: Eye Color

Let's take a simple hereditary trait, such as eye color. A particular gene influences the amount and type of pigment produced in the iris. Depending on the alleles inherited from both parents, the protein produced differs slightly, which results in a different eye color.

Family Resemblance: A Genetic Explanation

If a child resembles their parents, it is no coincidence: for each gene, they have inherited one allele from their mother and one allele from their father. It is this unique combination of alleles, inherited from both parents, that explains both family resemblances and differences between siblings (who never inherit exactly the same combination, except for identical twins).

An Important Distinction

Gene and trait should not be confused: the gene is the portion of DNA (the information), the trait is what is observable in the individual (eye color, for example). A single trait can result from the interaction of several genes, and the environment can also influence certain traits (height, for example, depends on both genes AND diet).

Key Takeaway

The path of information follows a clear logic: DNA → gene → protein → observable trait. It is this chain that connects a simple chemical sequence to the visible diversity of life.