How many generations does a gene get passed down?

Question

We are genetically related to our ancestors up to how many years ago?

Answer 1

Basically, a child gets half of its genes from its mother and half from its father. Since each of those parents got half their genes from each of their parents, the child can attribute 25% of their genes to each grandparent. That percentage is halved again for each generation. Great-grandparents provide 12.5% each, great-great grandparents 6.25% each. We are genetically related to every direct ancestor as far back as you can imagine, but it is up to you to decide how much is significant. For example, my 12th great grandfather was Native American. That's 0.006% of my genes - I'm not about to walk around claiming to be an Indian. However, if I were a male descendant of sons of sons all the way back to him and I compared Y-chromosome  DNA test results to those of descendant of another son of my 12 great-grandfather, there would be some DNA in common. 11th cousins... nearest common ancestor lived over 300 years ago, and yet there'd be a small genetic connection.

Answer 2

DNA is in your heritage, as far back as they go.. no one can positively say how far back that could be.  There isn't any "cut off" point.  

I'm not any expert on genetics, which differs from genealogy. However.. you need to remember about dominant and recessive genes and how they work.  You can have a gene from an ancestor WAY WAY back, for (example) blue eyes or medical things.  It will appear AT RANDOM.  If diabetes is in your background for instance.. it will not show up in every desc or every generation.

Answer 3

Recessive genes can pop up from several generations ago.  Case in point: My grandmother had red hair and passed this gene along to two of her five children; however, my mom had light brown hair, and my brother was a blonde, yet one of his sons has my grandmother's red hair.

Answer 4

My father, who knows a lot about biology, learnt that it passes down 7 generations. But I didn't want to know more when he said so

Answer 5

Theoretically, forever. However, 10 generations ago, it would require 512 persons to create everyone of us, so each of those persons passed down 1/512 of your DNA. By the time one goes back 33 generations, it would have required more persons than are alive on earth today! (And people get excited when I say that 4 generations ago grandpa married a first cousin! It is impossible for that to NOT have happened!)

The thing is, there are dominant and recessive genes; DNA changes, mutates, so while the gene might have originally been for one color of hair, natural radiation changed it and now the descendants have a different color of hair (or eyes, whatever).

A DNA test is for FAR DISTANT ANCESTORS, meaning that, for certain, genes are passed down for a long, long, long time.

See the website, www.familytreedna.com and the National Geographics Genotype Programs for further details.