The problem is there is no mythical “100% Irish” population to compare to except an arbitrarily defined one. And then what do you do when your population contains Brian Kelly, who turns out to be more closely related to some people in Norway than he is to his next-door neighbors. This is the same problem of “cladistics meets the vernacular”-- where apes are monkeys and humans are fish. Because genes don’t conform to our arbitrarily drawn country boundaries.
There may be some ancestral “first family of Ireland” (the first humans to set foot in that land) but we have no access to their genome.
That’s certainly possible. It could be that I read what you wrote and was reminded of things that other people have written that I disagree with, and was arguing against that instead. A bad habit, for which I apologise and will try harder to avoid. In any event, thanks for the clarification, which makes a lot of sense.
Fair enough, and it looks like I wasn’t clear enough either. 
Do any of the testing sites actually try to separate Irish from the rest of Britain? Because I think that would be very difficult to do in any even vaguely scientific way. I mean I know the whole testing process isn’t that scientific but that would be ridiculous.
The 60,000 year number was based on genetic testing of other Andaman Islanders, and was assumed to be applicable to the Sentineliese as well. North Sentinel Island is pretty much smack dab in the middle of the Andaman Island chain, so it’s the most parsimonious assumption to make. When new data taken from the Andamanese Islanders became available showing they probably originated 26k years ago instead of 60k, it was once again assumed to apply to the Sentinelese. If anyone believed the 60k year data for the Sentinelese before, there is no reason not to believe the 26k year data now. That’s pretty much how science works.
Sorry, “it could happen” isn’t a valid cite either.
Do you even know what the 60,000 figure was based on? :dubious: If so, please state the actual evidence.
As John Mace says, both the 60,000 year and 26,000 year figures are based on the assumption that the Sentinelese are closely related to the other Andaman Islanders. Given that photos show them to be physically identical in appearance to the other Andamanese, there is absolutely no reason to suppose that that they are a completely independent population. And it’s extremely unlikely that a population of a few hundred people could have persisted in isolation for many thousands of years on an island only 23 square miles in area without any contact with others, especially when North Sentinel is only around 20 miles from the main Andamans.
There’s your problem. Around 1800 or so, sailors discovered the Andaman islands, and wasted no time spreading their DNA and germs among the natives. Killing over 7000 Andaman Islanders and a way of life for the islanders. Now, they never went to Sentinel island because, well, they got shot or killed for doing so.
Since 1800 Andaman Islanders have had European DNA in in their families. Sentinelese have not. Not for 60,000 years.
Your study excludes the Sentinelese people so it obviously is not meant to apply to them. It excludes them because no one has ever tested them, because, well you know how that would turn out.
Isn’t that amazing, 2 very different societies, only a few dozen miles apart and they haven’t even rowed a boat to get there. Could be because India enforces a 3 mile exclusion zone around the island.
23 square miles of total isolation. It might as well be on the moon.
Here is a few reasons why they are isolated.
No natural harbors, nothing of interest.
North Sentinel has no natural harbors, so there’s no ideal spot for a ship to take shelter from in a storm, and furthermore, the island is surrounded by a ring of submerged coral reefs that prevent large ships from approaching.
https://www.wheresmamba.com/single-post/North-Sentinel-Island
Beware though, they claim 60k for the isolation too.
Sorry, it can’t be.
Sorry, it can’t be. Most optimistic linguists claim they can trace Indoeuropean roots some 7000 years ago. And languages in that family are very diverse. Now, Sentilenese (judging by few known overheard phrases) is related, even similar to a degree, to Andamanese languages (like modern day Polish and Russian, let’say). Hence, there must have been a contact at least 1000 years ago. Even if they didnt originate from Andaman islands, even if language transfer happened to a 60000 yrs olds society, there has been a recentish contact.
EDIT: Apologies for double post - I can’t edit it or delete it for some reason
And more.
They are thought to be directly descended from the first human populations to emerge from Africa, and have probably lived in the Andaman Islands for up to 60,000 years. The fact that their language is so different even from other Andaman islanders suggests that they have had little contact with other people for thousands of years.
https://www.survivalinternational.org/campaigns/mostisolated
What you don’t seem to understand is that the study that came up with the figure of 60,000 years also excluded the Sentinelese. The figure is based on the Andamanese in general. There is no direct evidence that the Sentinelese have been isolated for 60,000 years, regardless of how many websites repeat that figure. As we have said, the figures of 60,000 and 26,000 are based on the same kind of evidence and the same assumptions, but the latter figure is more recent and based on better data on the Andamanese. And in neither case do those figures imply that the Sentinelese have been isolated from the other Andamanese.
Once again, I’m going to ask you to provide a cite, based on published peer reviewed evidence in a scientific journal, that the Sentinelese have been isolated for 60,000 years. I don’t think you understand where that figure comes from or how it was derived.
(With all due respect, I can’t help be be reminded by this conversation of this cartoon on “science hell.”) 
I’m not sure why the Andaman Islanders would need a “large ship” to get from their island to N. Sentinal (about 20 miles away). And being primitive H/G’s, they wouldn’t have had “large ships” anyway, so they wouldn’t have to worry about that. I also doubt that India has been enforcing its “no go” rule for 26,000 years. It also doesn’t take “thousands of years” for languages to change enough to be mutually unintelligible.
Not for 60,000 years. Not even for a century.
Which is my point. They’re not on the moon. It’s absurd to believe they have been isolated from the other Andamanese when they are so close.
Canoes don’t need harbors and can easily pass through coral reefs. The Sentinelese would have been of interest to the other Andamanese simply for being other people.
Agreed that the Sentinelese have been isolated for the last few hundred years from European contact. That does not mean that they have been isolated from their near neighbors.
Again, poorly formatted web pages do not constitute cites.
Every one of them is poorly formatted too? Well color me embarrassed.
Seems National Geographic’s poorly formatted too then;
*Their awareness of the ocean, earth, and the movement of animals has been accumulated over 60,000 years of inhabiting the islands. Oral history teachings and their hunter-gatherer lifestyle might have prepared them to move deeper into the forests after they felt the first trembles of the earthquake. *
(Talking about how the Sentinelese survived the earthquake and tsunami in 2004.)
And let’s see, A search for *Sentinel Island 60,000 years *
returns About 198,000 results (0.78 seconds)
A lot of opinion there John, but no facts.
Not that this actually means anything, but searching for “‘Sentinel Islands’ 26,000 years” returns 3,340,000 hits.
It’s the nature of a Dope thread to sidetrack itself with some picayune sidebar that seizes upon an offhand remark intended to serve as a pithy summary of a complicated topic, and then turn outliers into ammo with which to diminish credulity for the overall point being made.
I love that 
but it is not useful in creating understanding. So forget about the Sentinelese, except to the extent that if they are indeed an exception, they prove a general rule that genes flow across most populations in remarkably nimble ways.
We look around us and we see fellow humans who are phenotypically different in some way; we notice also that some phenotypic traits cluster in such a way that groupings seem to emerge. We then apply an observation that members of such groups often have a common perception of the geographic location of the ancestral population from which they are descended.
Overlaid on top of the complex reason(s) for which various groupings emerge are social, political and psychological layers that collectively distract from a discussion around the biology of the human species. Some poor homie cannot even ask a question about genetic makeup without worrying that someone will take him to task for sneaking racism in by the back door. Ai yi yi.
Let me completely retract my original response and change it as follows:
Anyone can claim “100%” descent from any ancestor. (Dibs on Solomon for CP. LOL )
Were they to do so, they would demonstrate they have no idea what they are talking about. In general, the way to understand genetic ancestry is to first gain an understanding of how humans populated the world. From there, learn how various genetic markers are used as proxies from which gene flow can be approximated.
WRT the various present-day populations in Europe, anyone who thinks they are “100% descended” from any ancestral population is as wrong as the individual who thinks modern populations have somehow been so thoroughly homogenized that gene variant frequencies do not emerge for groups created by an average claim for an ancestral population defined by their geographic location.
You jumped from “biological parentage may not match believed parentage” to “infidelity”.
You’ve been here long enough to know that moving the goal posts doesn’t work. Hasn’t in the past, won’t now.