believer,
If all living species were descended from a single breeding pair that lived only two thousand years ago, there would be very clear genetic traces of the event visible in the DNA of every animal. If mutations in animals' DNA had only had 2000 years to accumulate, every member of each species would be exremely genetically similar across the entire genome. This is simply because 2000 years of mutation does not produce a large amount of heterozygosity.
This is the opposite of what we find. The diversity in DNA within each species living on the planet today is far too high for us to accept that such a scenario is correct. It would have required mutation rates far higher than anything that has been observed in the natural world.
So, on the basis of the genetic evidence, the entire flood story should be dismissed out of hand. It is not a literal truth.
Mick
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