Is there a gene for multicolored hair or is my hair color a result of a mutation?

My mother's hair was black and she grayed at a very early age.

My father's hair was either dark brown or black.

My siblings have Brown, Reddish-brown, and blond hair.

I have black hair... for the most part.

We are all Caucasian.

My hair used to be totally black. It would lighten to very dark brown in the summer and go to total black in the winter. My hair still changes color with the summer and winter but now I have random vibrantly colored brown, red, and blond hairs. Not just stray hairs but lots of them (although the majority of my hair is still very dark brown/black). What is causing them?

Is there a gene for multicolored hair or is my hair color a result of a mutation?

You don't say if you're a male or female but my guess is female ... and here's why ...

The most common way in which hair color variety is produced, at least in other species like cats (ie calicos) is through random inactivation of one of the two X chromosomes present in each hair cell of a female. Exposure to UV light (ie sunlight) is thought to somehow influence the pattern that is actually formed during embryogenesis of which cells get an active vs an inactive X chromosome.

Most probably science doesn't know what's going on with you though. But here are some additional possibilities:

1. A new phenomena known as "brindling" (see Wikipedia entry "brindle") was discovered this year; it's not yet described in humans, but maybe you're #1!

2. Certain variations in the CDKN2A gene along with some in the MC1R gene, which is the gene responsible for at least some redheads, only seem to make themselves known later in life. One example shifts color change from ~38 years to ~58 years of age.

3. Premature graying just by itself is thought to have numerous independent causes.

4. There are several variations in a DNA repair gene known as ERCC2 that affect hair color and graying, but their main effect has to do with how the skin repairs sun damage, and hopefully you haven't noticed any problems in that regard.

5. Lastly, there are some rare conditions involving either hair texture (in particular, brittleness) or ingested mineral issues (like, chromium, selenium, etc), but again, hopefully you aren't being exposed in some seasonal manner to strange chemicals.

Is there a gene for multicolored hair or is my hair color a result of a mutation?

Its probably a genetic dominant trait. The black hair is the most dominant trait, however there are alot of mixed recessive genes too. In the future your children will probably have red, or blondish hair.