Hacker News Reader

Comment by RoyalHenOil | Hacker News Reader

This is the number supported by DNA evidence. There will be a margin of error.

The bigger issue, for me, is that I'm not sure how they can rule out the possibility that there were lots of other people around at that time whose lineages gradually died out. Modern genetic lineages may trace back to 1280 people (+/- the margin of error), but it seems pretty dubious to assume that those were the only people living at that time. It seems highly likely to me that there were infertile people, people who died young, people whose only living children were infertile or died young, etc.

(I did not read the original paper, so maybe they accounted for this, or maybe they that specify that this was a genetic bottle neck for modern humans, but not necessarily the actual size of the population.)

View on HN

"1280 people" is just a misleading simplification early in the linked article. Both the news article and the original paper speak of 1280 breeding individuals.

Also, the way population dynamics work, lineages tend to die out quickly or not at all. Isolated populations can die out gradually, but it takes exceptional circumstances for a population to survive in the long term while remaining isolated.

There is a minimum in the fossil record at that time. There may be other explanations for it, but one very reasonable one is that there just weren't very many skeletons to potentially fossilize.

Certainly. However, I am still highly doubtful that there were only 1280 people alive at that time. I'm not sure that this is what the article is claiming; however, it is written in a way that makes it very easy to come away with that message (as evidenced in this comment section).

What are the chances that every person alive today, for example, will still have living descendants in 400,000 years? If people 400,000 years in the future do a genetic study on themselves to determine how many of their ancestors were alive in the year 2023, what percentage of the 2023 population will they be able to account for? My guess is a fair bit lower than 100%.

"there were lots of other people around at that time whose lineages gradually died out"

It seems to me that if those lineages aren't in the DNA data, then they didn't --in the intervening years-- intermix with the lineages in the DNA data.

So, ipso facto, those lineages went extinct, and the 1280 ancestors posited in the study are the non-extinct lineages. QED.

That's correct.

Now, that doesn't necessarily mean they were isolated from each other, however. If we suppose that the population was actually 5000 people (just an example; I have no idea if this is a realistic number), then some percentage of those people died with having children, some may have seen their children die, etc. Of the 1280 people who still have living descendants, many of them would have had children with those people who did not, but those children (or grandchildren, etc.) eventually did not have any children themselves.

Within your own social circle, you likely know some people who will still have living descendant generations from now and some who will not.

If those lines died out from intertribal competition though, it wasn’t a near-extinction era. Some slightly less competitive group could have made it into the present day in that case.

Exactly: it's really hard to tell if "the environment" took out the other hominids, or if the descendants of the 1280 took them out.

"Hmm, this monkey looking thing isn't as tasty as a wooly mammoth, but it'll do."

(it's not like chimps don't catch and eat other primates)

> I did not read the original paper, so maybe they accounted for this

Then why say it's an issue?

I'm not saying it's an issue with the research. It's very likely the researchers thought of this.

It IS an issue with the article linked here, since it does not explain the research and causes readers to walk away believing there were only 1280 people.

They haven't.

Reply on news.ycombinator.com