How many anscestors?

[whatdoiknowanyway]

Recently I watched a T.V. program which suggested that everyone alive today, could trace their descent, via michrocondrial D.N.A. to one female. (I must get out more often)

 

All very reasonable, I thought, it only takes one genetic mutation at the right time and place.

 

But, when I extrapolated back from myself I came across the following dilema.

 

I have two parents, four grandparents eight great grandparents and so on. Taking tha average generation gap to be 25 years, it doesn't take too long before my direct ancestors outnumber the total population of my country, and not a great deal more before I have more ancestors than could have lived in all history.

 

This can only mean that throughout its history, the human race has interbred.

 

Is there any other possible answer?

 

Where"s my banjo?

[Tormod]

Wasn't this discussed recently? There is a very simple and logical explanation to this.

[Boerseun]

'Course the human race has interbred. You don't call the guy in the living room 'Uncle Dad' for nothing, now do you?

 

Any case - the incest taboo as a general rule amongst most human societies is also only strictly enforced amongst immediate family members, i.e. brothers, sisters, moms and dads. Cousins are fair game, legally, as well.

 

Having two or three kids is a recent development. In the old days, people had lotsa kids to cope with high mortality rates, as well as a huge lack of rubbers. Let's say five kids surviving to the stage where they could procreate was the average. That means that one single individual would have 5x5x5x5x5x5x5x5x5x5 descendants in only ten generations. That's a whopping 9,765,625 kids in only ten generations! From a single ancestor! Now reverse the argument:

You have two direct ancestors (mom and dad) - regardless of average family size, you could only ever have two. They've had two each, and so on. In other words, ten generations ago, you've had 2x2x2x2x2x2x2x2x2x2 ancestors. That's only 1024!!!

 

Yep. They did indeed interbreed. Ask my cousin Jeb.

[skuzie]

You can find a related post here:

 

http://hypography.com/forums/biology/6393-computer-model-our-ancestry-mechanics-evolution.html

 

:confused: