Related?

[Boyar Son]

If humans only at one time existed in few numbers, maybe at two (parents), could it be possible that we're all related?

[Korlon]

Considering the extremely negative effects of inbreeding, I don't think so. We'd all be stunted with bad health and one disease that affects that one person would affect everybody else, unless some relatively large scale mutations of our genetics were to happen, but that would take a very, very long time.

[Dayman]

http://en.wikipedia.org/wiki/Mitochondrial_Eve
http://en.wikipedia.org/wiki/Y-chromosomal_Adam

[Richard]

We ARE all related...I'm sure wikipedia will have something to say about 'most recent common ancestor'.

[H_man]

We're a severely imbred species. If you trace back your roots to the time of Jesus, there were already 50 billion (is that correct, Short History of Nearly Everything fans?) matings that occured to make you. Thus, that number being greater (100 billion humans), even to 2000 years ago, than all the humans that have EVER existed, we can only conclude that you are the product of intense imbreeding. As long as this imbreeding occurs with a group at least 2 generations from you, I assume one's offspring should be perfectly fine.

[Simetrical]

Certainly we're all the product of a small group, at most. Note that generally populations drift together. You'd have a group of primates that all drifted gradually toward humanity together, not a single person who was suddenly human when his parents were not. (After all, that person would then not be able to breed with anyone.) So inbreeding would not have been a problem at any point, necessarily. Regardless, the effects of inbreeding will, like anything negative, be selected away after enough generations.

It should be noted that it's believed that not just humans, but all life on Earth is descended from a single organism billions of years ago. This is the single-origin hypothesis.

[CtrlAltDe1337]

If humans only at one time existed in few numbers, maybe at two (parents), could it be possible that we're all related?

Yes...

[ajm317]

Just to throw up one more wiki link:

http://en.wikipedia.org/wiki/Most_re...ommon_ancestor

However, Rohde, Olson, and Chang (2004)[3], using a non-genetic model, estimated that the MRCA of all living humans may have lived within historical times (3rd millennium BC to 1st millennium AD). Rohde (2005)[5] refined the simulation with parameters from estimated historical human migrations and of population densities. For conservative parameters, he pushes back the date for the MRCA to the 6th millennium BC (p. 20), but still concludes with a "surprisingly recent" estimate of a MRCA living in the second or first millennium BC (p. 27). An explanation of this result is that, while humanity's MRCA was indeed a Paleolithic individual up to early modern times, the European explorers of the 16th and 17th centuries would have fathered enough offspring so that some "mainland" ancestry by today pervades even remote habitats. The possibility remains, however, that a single isolated population with no recent "mainland" admixture persists somewhere, which would immediately push back the date of humanity's MRCA by many millennia. While simulations help estimate probabilities, the question can be resolved authoritatively only by genetically testing every living human individual.

Other models reported in Rohde, Olson, and Chang (2004)[3] suggest that the MRCA of Western Europeans lived as recently as AD 1000. The same article provides surprisingly recent estimates for the identical ancestors point, the most recent time when each person then living was either an ancestor of all the persons alive today or an ancestor of none of them. The estimates for this are similarly uncertain, but date to considerably earlier than the MRCA, according to Rohde (2005) roughly to between 15,000 and 5,000 years ago.[5] [2].

It should be noted, as the Wiki article explains, that this does not imply that there was only 2 people in Western Europe in AD 1000, or that there was only two people at any point in human history.

EDIT: Judging from the talk page for the Wiki, the time estimates are a bit dubious. Still interesting though.

[Richard]

If humans only at one time existed in few numbers, maybe at two (parents), could it be possible that we're all related?

I don't think you'd have to go quite as low as two for that.

[sephodwyrm]

The critical information form the wiki article:

Allan Wilson's naming Mitochondrial Eve[4] after Eve of the Genesis creation story has led to some misunderstandings among the general public. A common misconception is that Mitochondrial Eve was the only living human female of her time — she was not. Had she been the only living female of her time, humanity would most likely have become extinct due to an extreme population bottleneck.

The first human (technically) would have cousins and relatives that are very close to humans (maybe just by a gene or a few).

[Richard]

sephodwyrm, that appears to be referring to the most recent common female ancestor; not the first female human. I'm probably wrong and don't feel like digging for my year 13 biology textbook though so someone can correct me if they wish.

[Bokks]

Well, Boeing and Richard beat me to the punch, and H_man brought the fact that the relation can be separated by two generations and you'll be fine.
I did want to point out, though, that humans are genetically 99.9% alike to eachother... every human (I think i said that somewhere else, recently, too) despite the vast isolation so many people have had over the millenia.
While it is bizarre to think about, it's no-where near mating with a sibling. With are all, however, effectively cousins to eachother!

Oh, yes, and Richard, you are right, it's all about the most common female ancestor, not anywhere near the first female from whom we're all born. It's still icredible, however, to think that the first tribe of homo sapiens sapiens was interconnected enough so that any female could be a common ancestor to everyone. It also makes you wonder if there's anyone alive that's not related?
Well, I guess there'd have to be a whole community for that to work, since only one person who'se not related would last just one generation...

[The Super Pope]

1000AD? bs