Types of human gene mutations, hereditary and somatic mutations

Nature of Gene Mutations, Inherited and Acquired Mutations, Polymorphisms, Mini- and Microsatellite Sequences

The nature of gene mutations is like a typo in a book

Sometimes it's one letter wrong. Sometimes words or sentences are inserted, deleted, or jumbled. Since DNA holds the blueprint for building proteins, even small changes can be important.

But not all mutations cause problems. Some do nothing at all. Some might even be helpful. Like in language, where changing a word slightly might still keep the meaning or change it entirely.

Inherited and Acquired Mutations

Mutations come from two main sources: what we’re born with, and what happens to us along the way.

Inherited mutations are passed down from our parents. Present in somatic cells. These changes have been in our family tree for generations, like genetic heirlooms.

Acquired mutations develop during a lifetime. Maybe a cell makes a mistake when it copies DNA. Or maybe something in the environment: a bit of UV radiation or chemicals, causing a change. These mutations are not found in every cell and are not passed on to children, but they do affect the behavior of the particular cell.

Polymorphisms:

Every now and then, DNA differences aren't actually "mutations" in a negative sense at all they're just variations. These are called polymorphisms.

Let them be British vs. American spelling differences. "Colour" and "Color"  same idea, different spelling. Polymorphisms are common in the population and usually not problematic. But they do make us unique. They can account for why people have differing eye color, or why one person can metabolize caffeine differently than another person.

Minisatellites and Microsatellites

DNA is not always serious instructions. Sometimes, it's just.repeats. Repeated repeatedly.

Minisatellites are repetitions of medium length, like a sentence copied again and again.

Microsatellites are briefer, just a word, or even a syllable, copied and copied.

These copied regions do not usually hold useful instructions, but they vary greatly from one person to another. That makes them very useful when we have to identify what makes people different based on their DNA like no two barcodes being the same.

They're also useful markers in genetics because they can move more quickly through generations so scientists can trace how the DNA shifts and transfers between one population and one family to the next.

References

1. Strachan T, Read AP. Human Molecular Genetics, 4th ed. Garland Science, 2010.
2. Watson JD et al. Molecular Biology of the Gene, 7th ed. Pearson, 2013.
3. Alberts B et al. Molecular Biology of the Cell, 6th ed. Garland Science, 2014.