QUOTE (Prau123 @ Jun 25 2012, 02:08 AM)
That's not a bad explanation Trismegistos. In fact, that's what I wanted to say in response to Jc2's question regarding Denisova admixture in Southern Philippine "Australoid" groups (such as the Manobo and Mamanwa) and the Melanesians/Papuans east of the Wallace line.
I too think that the Denisova hominin survived only east of the Wallace line (northern Sahul) and parts of Siberia. What happened to the Denisova hominin's inbetween northern Sahul and Siberia? My guess is that the Toba eruption killed off the population between northern Sahul and Siberia. If not the Toba eruption, at least some other major climatic event. This explains why some Philippine Negritos (such as the Aeta, Ati, Agta, etc.), Malaysian Negritos, Andamanese Negritos, many Southeast Asian Mongoloids, and many Northeast Asian Mongoloids don't have Denisova hominin admixture.
Just one correction, though. The Denisovan admixture is presently found only in Wallacea and among Mindanao negritos. It is now absent even in all parts of Siberia, even near to the original site where they found the fossils of a pure(?) Denisovan man in Denisova cave. Again, the fossils of this ancient relative of modern humans is first found in Denisova cave, hence the term Denisovan or Denisova hominin. That doesn't mean Denisovan originated near Denisova cave.
You are right. Many other relatives of humans or other hominins also died during the Toba erupton, including much the Denisovans, almost all Homo erectus, etc. Even the neanderthals of Europe died off during the climate change post-Toba eruption. Some denisovans obviously were spared or were able to survive to become incorporated in the genome of Papuans, of certain negritos in Mindanao, and of the Australian aborigenes.
QUOTE (Prau123 @ Jun 25 2012, 02:08 AM)
Getting back to our original discussion. The Denisova hominin lived east of the Wallace line in northern Sahul prior to the arrival of the Papuans (or the ancestors of today's Papuans who may have a recent common ancestor with the Negritos of the Philippines, Malaysia, and the Andaman islands). The Papuans/Negritos that migrated east of the Wallace line to northern Sahul were the Papuans/Negritos who acquired the Denisova admixture because they interbred with the Denisova hominin that survived there which is what you said. But the Papuans and Negritos who remained west of the Wallace line never received the Denisova admixture such as some of the Philippine Negritos, Malaysian Negritos, and the Andaman Negritos.
By the way, I read the Razib Khan link that you cited which was originally posted by AnybodyKiller: http://blogs.discovermagazine.com/gnxp/201...tipode-of-asia/
I read some of the discussion below that article, and one of the posters, Pavlova, was mentioning that the Papuan AX-ME cluster in the chart below should be closer to the Indian cluster, because in many other studies and PCA plots, Papuans are closer to Indians than to Southeast Asian/Northeast Asians. But in this plot the Papuan AX-ME cluster is closer to the Southeast Asian/Northeast Asians as compared to the Indians. Pavlova explains that the Papuan AX-ME cluster may actually be a Melanesian cluster as oppose to a true Papuan cluster; Melanesians have Austronesian ancestry and this evident in the fact that many Melanesians speak an Austronesian language. If the Papuan AX-ME cluster is in fact a Melanesian cluster, then that would explain why the Papuan AX-ME cluster is closer to the Southeast Asians and Northeast Asians as compared to the Indian cluster. The same could be said of the Malaysia Negrito cluster. Since the Malaysian Negritos have interbred with the Southeast Asians, that explains why they too cluster closer to the Southeast Asians/Northeast Asians as oppose to the Indian cluster.
But this does not affect your argument in any way, Trismegistos. In fact, it may show just how close all Australoids are (Indian ASI, Philippine Negritos, Malaysian Negritos, Papuans) which strengthens your argument that Melanesians/Papuans have a common ancestor with the Negritos of the Philippines, Malaysia, and the Andaman islands. If Papuans are truly close to Indians according to Pavlova, then that forces the other Negritos to be closer (or just as close) to Indians, hence it's one large close knit family.
Nice observaton there by Pavlova. That could explain some inconsistencies.
Interbreeding or admixtures do or did occur between Austronesians and Negritos or Papuans for that matter but not in a major way as that Denisovan admixing with Papuans. Admixtures with some exceptions primarily become significant only in later times as the world gets smaller. This is because of the bias of marrying only with your own kind or only in the same social class or same clan or same tribe and therefore the taboo against ethnic mixing and for that reason, we have so many ethnic groups and there are many languages as there are ethnic groups. That's the Tower of babel paradigm.
Later on organized religion and politics enforced that taboo even more like the various caste structures in India and the castelike structures among ancient Southeast Asians. More so of the bias between very divergent lifestyles. For eg, between those with Agrarian lifestyle with the somewhat hunter-gatherer lifestyle.
And so you have indigenous groups which seemed to be greatly isolated from other ethnic groups despite the relatively very narrow geographic distance because of such sociocultural barrier which formed a genetic barrier as well. For eg. the Sambalic-speaking Aeta negritos with purely K* haplo with the Sambalic-speaking agrarian Kapampangans of O haplogroup, their contacts would be solely for trade purposes, Aeta negritos bartering their gold in exchange for trade products of the Kapampangan. The Aeta negritos from Zambales if we are to believe those studies mentioned have achieved relatively Genetic isolation free from admixtures for so many periods despite the very near distance with the mainstream populations. The same goes for other indigenous groups in relation to the dominant or mainstream agrarian ethnic groups. Exceptions would be the sanctioned royal intermarriages between ethnic groups to forged some political alliances or peace treaties.
What caused the genetic affinity/closeness and the somewhat opposite, the heterogeneity, the latter of which most would quickly attribute to mainly due to admixtures between ethnic groups that are indigenous with migrants from the backmigration for e.g, despite all those above mentioned sociocultural barriers forming relatively a genetic barrier, is probably due to bifurcations/splittting primarily as Australoids transitioned to becoming the Southern Mongoloids. E.g., Paragroup K splitting into becoming the Mongoloid, O and N haplogroup as they formed newer ethnic groups which went on separate ways and so on and so forth. Eventually, the various transitional groups died off due to those calamities. Having the same ancestral lines as we go many generations backward in time and go up the phylogenic tree, make these various ethnic groups cluster together in closer genetic affinity. Thus, I deduced that admixture only factored in secondarily to common ancestral phylogeny as the former becomes a major influence only recently (as the world gets smaller) in bringing various separate but contiguous ethnic groups closer together in genetic affinity. Implied in this also that O haplogroup which includes the majority of Austronesians, the East Asians and the rest of Southeast Asians originated in Southeat Asia from their K ancestors who went to Southeast Asia. Mongoloid neonetization could occur right in our own backward here in Southeast Asia as brought about by the Toba eruption and the various climate changes, making it possible. The selection bias due to sociocultural divide did ensure that genetic lines
would not lost their Mongoloid phenotype by intermarrying with Australoids negating Admixture phenomenon from causing HOMOGENEITY or homogenization in phenotype.
Of course, there are exceptions like the major admixture of relatively recent haplos between Mongoloids and the Caucasoids forming the Uyghurs.
Admixture between Denisovan and the Papuans could be somewhat facilitated by their having similar lifestyles. Thus, there was no sociocultural barrier to genetic exchanges. And that admixture had occured early on (Papuan founder lines admixed earlier with Denisovan lines) ensuring their descendants down the line would always carry their Denisovan genetic heritage from that earliest point of many tens of thousands of years ago spilling over to the present.
QUOTE (Prau123 @ Jun 25 2012, 02:08 AM)
Now it should be mentioned that the poster, Pavlova, is arguing for a Northern Route for the arrival of Mongoloids and Papuans into Eastern Eurasia. Pavlova does cite studies for his/her reason. Here's a part of Pavlova's discussion:
[I disagree that Papuans are more related to East Asians. Nearly all genetic studies I’ve seen show that Papuans are the closest to South Asians. Note that the b]Australoids originated from South Asia. Also, Siberians and Native Americans seem to be the furthest away from Papuans out of all non-African populations.
Among Europeans, Northern Europeans are genetically more related to Papuans than Southern Europeans are to Papuans. The difference in FST between European-Papuan and Northeast Asian-Papuan is negligible. This probably means Papuans split off from the same Eurasian branch as the Europeans and East Eurasians[/b]]
In your statement which I bolded, you said:
Papuans went to the Northern route together with the Mongoloids to East Asia. Then yet he disagreed that Papuans are more related to East Asian mongoloids? I find that strange. Then, he said further that Siberians and Native Americans seemed further away from Papuans. It doesn't make any sense when the Papuans are coming from the Northern route?
QUOTE (Prau123 @ Jun 25 2012, 02:08 AM)
What Pavlova is saying is that from Africa, humans migrated to the Middle East, then to Southern Europe, then to Northern Europe. From Northern Europe, one population went southeastward to form Papuans and Indians (hence why Papuans and Indians are close to one another), while a second population migrated eastward to form Mongoloids and Amerindians. Pavlova even says that "Siberians and Native Americans seem to be the furthest away from Papuans out of all non-African populations" which suggest that Mongoloids and Papuans (Australoids in general) do not have a more recent common ancestor with one another as compared to Papuans and Northern Europeans. This suggest that Mongoloids did not originate in Southeast Asia, but rather they originate up in northern Asia derived from Northern Europeans! This is contrary to many of the recent studies that we have been discussing on these boards that Mongoloids (or their ancestors) are from Southeast Asia coming from a Southern Route through India from Africa. This is also contrary to the Pan-Asian SNP Consortium findings that 95% of the Y-DNA haplogroups come from the south from Southeast Asia.
Pavlova also mentions on that in some studies Papuans actually appear to cluster closer to Northeast Asians than to Southeast Asians, and the explanation for that is because Northeast Asians have an Australoid component in them as well, namely Jomone. But I personally think that the Australoid component in Southeast Asians should be higher compared to that in Northeast Asians which would make them cluster closer to Papuans.
Here is a Razib Khan study that Pavlova cites that shows Papuans are indeed slightly closer to South Asians, Europeans, and West Asians as compared to Southeast Asians and Northeast Asians: http://blogs.discovermagazine.com/gnxp/201...abites-papuans/
I don't think there is conflict over what Pavlova said with the now generally accepted Southern route theory as proposed by the Hugo SNP study. I read all his posts regarding the topic and he never mentioned that he was against the Southern route. Though, it do appears at first glance, but all his statements despite being opposed by Razib Khan on certain areas can be reconciled with the Southern route theory.
I don't think he implied that there is no common ancestor between the Mongoloids and the Papuans. He never implied that the Eurasians went to North Europe and through the Northern route to become the East Asians and Amerindians, while the rest went the Southern route to become the Papuans and the South Asians in order to explain the relative genetic distance between Northeast Asians and the Papuans. The Papuans came from North Europe? Did he said or implied that?
Razib Khan even said the dangers of relying to old classical marker studies causing people to wrongly assume such deductions like "Siberians and Native Americans seem to be the furthest away from Papuans out of all non-African populations" which suggest that Mongoloids and Papuans (Australoids in general) do not have a more recent common ancestor with one another as compared to Papuans and Northern Europeans. This suggest that Mongoloids did not originate in Southeast Asia, but rather they originate up in northern Asia derived from Northern Europeans!
He said and I quote;
i think this is the problem. different marker sets will give different results because of this problem.[snip]
the power of the old classical marker studies is low to detect a lot of fine-grained differences. they’re good with african vs. non-african cuz that’s the cleanest distinction in the data set. fyi, for robust human phylogenetics i wouldn’t look at anything before 2005. the old stuff isn’t wrong always, but for fine scale stuff the SNP-chip studies are the best.
Now to reconcile what Pavlova said to that of the Southern route theory, which I think he never debunked anyway:
Mankind came from Africa and then went to South Asia (the Southern route theory) then to Southeast Asia, this is the path the Australoids went. The split came in there and went northwards to Central Asia specifically to Iran( Aryans splitting from the Indo-aryan group ), then to West Asia, becoming the ancestors of both Europeans, northern and southern. This explains why the Australoids like Papuans have affinity with the Caucasoids and the South Asians. Papuans together with the Australian aborigenes are considered as Australoids. And they are indeed closer with the South Indians like the Australoid Dravidians and thus they cluster somewhat with North Indians and the rest of the Caucasoids.
From Southeast Asia another split happened between Australoids like the Papuans and the would be Southern Mongoloid, Southeast Asians. While East Asians including Northeast Asians is a subset of these Southeast Asians. There is some subset of the Australoids particularly the Ainus who went up before the Southeast Asian mongoloids were formed, the latter went upwards as well becoming the Yayoi group which intermarried with the earlier Jomon group or Ainuids forming the Okinawans and the Japanese. The Jomon group or the Australoid Ainus are related to the Australoids like the Papuans. Since the Northeast Asian Japanese have Australoid admixture particularly the Jomon and Ainus, this explains why Pavlova said Notheast Asian would cluster with Papuans.
Some subset from this southern route who became the Southern Mongoloid then eventually becoming the Northern Mongoloid, went further northwards to become the Siberians, while another subset went to the Americas becoming the Amerindians. This explains why Siberians and Amerindians is farther away from the Papuans genetically speaking. Just looking at Geography, one can understand it clearly.
So you see, he never said or implied that Mongoloids like Northeast Asians did not originate in Southeast Asia nor did he said that Mongoloids came from Northern Europeans.