Types of DNA Mutations
A DNA mutation is when the normal gene sequence is altered. Gene disorders are the result of DNA mutation, so these DNA mutations cause gene disorders. Now there’s many ways DNA mutations can come about. First is hereditary, and this means the DNA mutation is passed from parent to child, so if a person has a gene disorder it doesn’t necessarily mean that their genes got messed up, it was just their parents’ genes had a mutation.
Now you may ask, “Well how did their parents get that gene mutation?” Well it could have been it passed down to them, or it could have been from one of these causes. One is called de novo which means it occurs only in sex cells or shortly after fertilization. Then we have mosaicism which occurs in a cell during an early embryonic stage.
Now the results of that is that certain cells are going to have this disorder, whereas you’re not going to see the results of the mutation in other cells. Then we have acquired mutations, or we could call them somatic mutations, this is due to environmental factors or replication errors, and when I talk about replication errors this means maybe an error that happened due to an incorrect base pair, or another way mutations can occur is if an error is made by the DNA polymerase while replicating a base.
This happens about once for every one hundred million bases, but a repair protein proofreads the code, so the mistake is usually repaired. Now, there’s a term called polymorphism which means that the differences in humans such as eye and hair color may have originally been the result of gene mutations but are now part of the normal variation of the species.
While these DNA mutations may seem like they’re all bad, sometimes they’re somewhat neutral and don’t really cause a problem and now they’re just a normal part of the variation of a species.