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Category Archive: Common ancestors

Oct 10 2006

Why we look different despite having identical ancestors

In the previous post in this series, I reported on a paper by Douglas L. T. Rohde, Steve Olson, and Joseph T. Chang and published in the journal Nature that said that if we go back about 5,000 years, the ancestors of everyone on Earth today are exactly the same. This date is called the …

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Sep 29 2006

The most recent common ancestor of all humans living today

In order to find the date of the most recent common ancestor (MRCA) of all the people living today, Chang started out by constructing a simple mathematical model of population mixing. (See here for some background to this post.) He assumed that the population is constant over time at some value N. He assumed that …

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Sep 28 2006

Some surprising facts about ancestors

In 1999, Joseph T. Chang published a very interesting paper in the journal Advances in Applied Probability (vol. 31, pages 1002-1026) titled Recent Common Ancestors of all Present-Day Individuals. To understand the paper, it helps to reflect a little on the mathematics of genealogy. One rock-solid fact of ancestry is that every person has two, …

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Sep 27 2006

My ancestor Narmer, the first Pharaoh of Egypt

While doing some research on my ancestors last month, I made the surprising discovery that I am the direct descendent of Narmer, who was the first Pharaoh of Egypt and lived around 3,100 BCE. Narmer (thought by some to be the same person as Menes) was not your run-of-the-mill pharaoh. He is a bona fide …

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Sep 26 2006

Our common ancestors

Darwin’s theory of natural selection implies that we are all descended from common ancestors. Most people who have doubts about the theory tend to think that this is a proposition that we can either choose to accept or deny. After all, no one was around to see it, were they? But Richard Dawkins’ excellent book …

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