Not true. There is no genetic evidence that humanity was ever reduced to a single breeding pair. This is called an “extreme genetic bottleneck,” which – if it had occurred – would have left an indelible signature in the human genome. There is no such signature. The evidence points to a population that never fell significantly below 3,000 breeding pairs in the last several hundred thousand years.
You can of course reject this, but you reject genetic science in doing so. You can also adhere to a literal reading of the “Noah’s Flood” myth, but in so doing you reject the conclusions of the sciences of geology, hydrology, biology, and physics.
I choose (with popes, bishops, and priests) to emphasize the spiritual and theological truths of these texts, rather than forcing upon them a woodenly literal reading.
StAnastasia
Then there are individuals among us without original sin? How can I tell?
http://www.philvaz.com/apologetics/p102.htm
Does Science Allow for a Literal Adam and Eve?
…Nonetheless, careful reading of your posts suggests to me that your conclusion about the scientific concensus is not based on the question of effective population size, but rather on other aspects of specific genes. Regarding effective population size, you affirm that in the last million years the concensus has been that it has been about 10,000, while Tenesa puts it at 7,500 in 2007. The important point of this is that when the genome in general is considered, the long-term effective population size of either 7,500 or 10,000 is consistent with the possibility of a bottleneck of just two individuals within the past 10,000 generations or so. For example, in Wen-Hsiung Li’s widely-used textbook, * Molecular Evolution*, he states (pp. 46-47): “The effective population size can also be much reduced due to long-term variations in the population size, which in turn are caused by such factors as environmental catastrophes, cyclical modes of reproduction, and local extinction and recolonization events. For example, the long-term effective population size in a species for a period of n generations is given by:
Ne = n/(1/N1 + 1/N2 + … + !/Nn)
where Ni is the population size of the ith generation. In other words, Ne equals the harmonic mean of the Ni values, and consequently it is close to the smallest value of Ni than to the largest one. Similarly if a population goes through a bottleneck, the effective population size is greatly reduced.”
My biology contacts tell me that if one uses the formula above for the effective population size, then a population which starts with 2 individuals and expands within ten generations to 10,000 individuals and then remained constant would have an effective population size of about 6,000. If it expanded quickly from 2 to 100,000, the effective population size would be about 12,000. Thus, with the uncertainties involved, a bottleneck of two is easily compatible with the effective population size of about 10,000 today.
and
Alec,
Well, I expected a very detailed and strong response from you, and you did not disappoint me! Unfortunately, I think we are beginning to go over the same ground. What I see developing in comments on this thread are three positions:
*]Divine revelation trumps certain present claims of natural science. Specifically, this occurs when a claim made on behalf of natural science crosses the epistemic boundary between natural science and theology. A prime example would be a natural scientific challenge to the Catholic Church’s definitive teaching that Adam and Eve actually existed as the two first true human parents of the entire human race.
*]Certain evolutionary theories appear to trump the truth of divine revelation.
*]Some deny that divine revelation requires belief in the literal reality of Adam and Eve.
**There is no doubt that Catholic teaching demands the literal reality of Adam and Eve, as has been superbly [ documented elsewhere](http://www.philvaz.com/apologetics/p100.htm). **You appear to place primary emphasis upon natural science in determining whether belief in a literal Adam and Eve is warranted, but you also mention #3. While #3 has been brought up in other posts, the key issue remains the reality of Adam and Eve as "*our first parents*" (cf. Catechism paragraphs 359, 375-377, 379, 388, 390-392, etc).