Polymorphisms
What is DNA polymorphism? Everything about its different types and their relevance in genetics.
Symptoms and Causes
Genetic polymorphisms are molecular markers that occur when a DNA sequence can take more than one form — they are variations in the DNA sequence. These may be present among different individuals or populations, shaping the inherent characteristics of each person or ethnic group (phenotype).
For the general population, the polymorphisms that differentiate species are quite evident, but those that make each person unique may be more complex to understand.
Polymorphisms can be classified into different types based on their structure, stability, and mode of transmission. The most notable include:
- Single nucleotide polymorphisms (SNPs): These involve the substitution of a single nucleotide in the genetic sequence and are distributed across various regions of the genome. They are highly significant, as they determine most of an individual’s phenotypic traits. Moreover, it is believed they played a role in human evolution by stabilizing certain point mutations within the human genome.
- Microsatellite polymorphisms or short tandem repeats (STRs): These are tandem repeats of short DNA sequences (between 2 and 7 nucleotides). They highlight differences among populations.
- Stable polymorphisms: Maintained continuously through natural selection across many generations.
- Transient polymorphisms: These shift relatively quickly in favor of another allele frequency.
The study of polymorphisms in genetics is highly valuable from both a societal and medical perspective. Medically, it allows for the identification of genes that make an individual or group of individuals more susceptible to developing certain diseases.
Numerous disorders are associated with a person’s genetic predisposition to develop them. For example:
- LRP1 polymorphism: cardiovascular disease.
- MTHFR, PON-1, eNOS, or NADPH polymorphisms: ischemic stroke.
- AGTR1 polymorphism: coronary artery disease.
What kind of doctor treats polymorphisms?
Geneticists study polymorphisms and are responsible for diagnosing them and proposing a treatment plan. Depending on the specific type of polymorphism, other specialists may also need to be involved.
