My little nephew Ty has dark brown skin and curly black hair.
His father, a Jamaican man, has much darker skin than he does.
His mother - my wife's sister - has much lighter skin than Ty.
She is white.
Ty's skin colour is a combination of his mother and father but there was only a 50 per cent chance of that happening. There was a 25 per cent chance that his skin could have been as dark as his dad's, as well as a 25 per cent chance that his skin more closely matched that of his mother.
Twenty years from now, Ty could meet someone just like him - a woman with dark brown skin and curly black hair and is the product of a union between a black man and a white woman. Their children could have the same skin colour as their parents but there is a significant chance - as high as 50 per cent - that their child could have the same light skin colour as their grandmothers.
Would anyone believe Ty and his equally dark-skinned partner when they would tell the world their white son or daughter is their biological child?
If Ty had been born with a skin colour much like his mother's, he likely could identify as white, even with that curly dark hair. And if he were to meet a woman just like him - same skin colour, same product of mixed-race parents - the odds are also as much as 50 per cent that these two white adults could have black children.
Again, would anyone believe them if two white adults would introduce their black son or daughter as their biological child?
Such are the mysteries of heredity, explored with joyful zeal in Carl Zimmer's book She Has Her Mother's Laugh: The Powers, Perversions and Potential of Heredity.
Heredity skips generations all the time, as we all know.
My adult biological daughter is shorter than both me and her mother. She's also shorter than three of her grandparents. Her shortness was clearly influenced by the one grandparent she is taller than - her grandmother (my mother), who is only four-foot-ten.
Yet Zimmer explains in his book that there is no one gene that determines an individual's height. Rather, height is influenced by as many as 100 genes, meaning that it is impossible to predict a child's adult height. There are simply too many interactions among too many genes to even hazard a guess.
Still with interactions, Zimmer notes that heredity and ancestry are two different things. I am a descendant of Nicolas Godbout, who came to Canada from France in 1651. From a genetic standpoint, however, I carry virtually none of his genes because so many generations separate us.
The difference between heredity and ancestry gets even funkier when flipped around. If I could identify a specific ancestor who lived 2,000 years ago, that person wouldn't just be related to me but to quite possibly every living person on Earth. The statistical model to show this was the case was first developed in the 1990s, Zimmer explains, years before genetic proof caught up to the theory.
Family trees aren't trees at all but intertwined hedges impossible to untangle.
Despite the fact we experience the world as individuals, our genetic identity paints a far more complex picture of who we really are. The view of humanity through a microscope more closely matches that seen of us from the vastness of space, as well as the depths of time.
We are as connected to other humans and to all other living things - not only in the present and in the distant past of hundreds of millions of years but also going forward until life ceases to exist on this planet - as the hair on our heads is linked to our toenails.
When I look at Ty, my eyes deceive me into believing he is not of me, nor I of him.
Yet I am Ty's uncle and he is my nephew.
The real, spectacular truth is that every man, everywhere and everywhen, is Ty's uncle.
And every boy, everywhere and everywhen, is my nephew.
