DNA Evidence for Noah's Flood and Abraham

1) Population in Abraham's time, and a discovery from modern genetics

Hundreds of millions of descendants of Ishmael and Isaac
The population in Abraham's time was very small.

Modern genetics suggests that the descendants of Abraham's two sons in the Bible, Ishmael and Isaac, now number in the hundreds of millions.

The Bible said Ishmael would become a great nation, and that prophecy is effectively confirmed in numbers.

2) A statistical gap between standard population models and the biblical story

Can one bloodline explode inside an already large population?
Hundreds of millions of descendants from one man, Abraham, in 4,000 years is hard to explain with the usual population models, such as evolutionary models of Homo sapiens.

If tens of millions of people were already spread across the world, it is statistically almost impossible for one particular bloodline to grow so explosively.

Conclusion: a population restart after the Flood, and a promise fulfilled literally

A tiny starting population, a promise of growth, and the evidence in our genes
If, on the other hand, you take the biblical record as it is, it explains itself naturally.
If humanity restarted from a very small number after Noah's flood, and Abraham's family multiplied in a special way as God promised, then hundreds of millions of descendants seems not surprising at all.

In the end, the DNA of hundreds of millions of people alive today is powerful evidence that the promise "I will make you into a great nation" is being fulfilled literally.

[For the dry, headache-inducing details of the research on Abraham's DNA, see the sources on the original post.]