genetic
Meaning of genetic: Genetic and hereditary are not synonyms, since every cancer is genetic in origin while only a small share of cancers are inherited.
Definition of genetic
Genetic describes anything relating to genes, the stretches of DNA that carry instructions for building and running the body. A genetic trait or disorder is one whose basis lies at least partly in a person's DNA sequence. The word says nothing about where the change came from, since many genetic changes arise for the first time in the individual who carries them.
How does it differ from the words used alongside it?
| Word | What it actually claims |
|---|---|
| Genetic | Involves genes; may or may not be passed on |
| Hereditary | Passed from parent to child through egg or sperm |
| Congenital | Present at birth, from any cause including infection or a medication |
| Familial | Runs in a family, which may reflect genes, shared environment, or both |
The four overlap but none implies another. A congenital heart defect may have no genetic basis at all, while a hereditary condition may not appear until middle age.
Where does a genetic change come from?
Two categories matter. Germline changes are present in the egg or sperm, so they sit in every cell of the body and can be passed to the next generation. Somatic changes arise later in one cell during life, from copying errors or from damage by ultraviolet light, chemicals or radiation; they affect only that cell and its descendants and are not inherited. This distinction explains the cancer example. Tumors are driven by somatic changes in nearly all cases, so cancer is a genetic disease of cells without being a hereditary one, and only a minority trace back to a germline change carried from birth.
Why do so few traits follow simple rules?
Single-gene conditions such as cystic fibrosis follow predictable inheritance patterns, but they are the minority. Height, blood pressure, diabetes risk and most common disease liability are polygenic, built from thousands of small contributions each too weak to notice alone, and they interact with diet, activity and exposure across a lifetime. Penetrance complicates matters further: two people carrying the same change may differ in whether the associated condition ever appears. This is why genetic testing often returns a probability rather than a verdict, and why some results are reported as variants of uncertain significance.
Used in a sentence
Genetic testing was recommended after a hereditary pattern of the condition emerged across several family members.
Good to know
A genetic condition is not always inherited from a parent, since some genetic changes arise newly in an individual rather than being passed down, a distinction relevant when family history is reviewed.
Word origin
Where “genetic” comes from
Formed from Greek genesis, meaning origin or birth, and the adjectival suffix -ic, together describing something relating to origin or generation.