How far can a recessive gene go?

[ChicanaChick]

My parents and others used to wonder why I was the only single left-handed member in the family. They found the answer but that recessive gene goes back to both my great-great grandfather and his dad (great-great-great grandfather) on my father's side.

That's so far and he's obviously long dead. How far can a recessive gene go?

[NamerOfStars]

Hand dominance isn't genetic; while genes likely play a part, it's not that simple. Also, whether an ancestor is alive or dead has nothing to do with what they contributed; that's decided when they're still ALIVE (absent some VERY strange circumstances, like bequeathing you their uranium collection).

As to that contribution... quick, get a piece of paper and sketch out a Punnett square of two heterozygous parents (big B and little b). Now, among the four offspring, you're going to have three phenotypically big B people- but the EXACT SAME number of big and little B's.

Recessive genes can go as far back as DNA goes.

[242plusInfinity]

They can go on FOREVER because they can be hidden by the dominant allele. I didn't know left handedness is genetic though. I'd have to ask someone before I believe that.

[ChicanaChick]

Yes it's affected by both genetic and/or environmental factors. It's also a recessive gene. I don't know anyone in my family (who are alive) or friends that are left-handed, just me. I wasn't taught so it's yeah that recessive got passed for sure, even though both of those guys are long dead.

[Sixgunsound]

Not a biologist, sorry.