The Ice Age
Before we embark on our journey, the basic understanding of
a great event that peaked at least twice during the migration of our ancestors
should first be understood. Theories surrounding the causes of ice ages are
still up for debate. The Earth’s wobble
and the amount of greenhouse gases are the main theories linked with the
occurrence of the ice ages. Ice
ages are marked by two periods, the glacial and interglacial. Glacial
periods are the period of colder temperatures while Interglacial are the relatively
warmer periods.
A glacial maxima happens during a glacial period when the
temperatures are at its lowest point; in essence it is the peak of an ice age.
Interglacial is basically the period between glacial maximas. As the
temperatures decrease, the Earth’s water accumulates as glaciers in the
northern and southern hemispheres; it is at these times when the polar ice caps
get closest to the equator. The source of water that form these glaciers are
mainly from the ocean, hence at a glacial maxima, the sea level is at its
lowest point which gives rise to shallow seabed and becomes what scientists
calls “land bridges”. The increase in ice in the European and Asian continents
and the emergence of land bridges especially in between continents, as
scientists know today, played a major role in the peopling of the world.
The last two glacial maxima had been estimated to be between
25,000 to 15,000 BP and 175,000 to 125,000 BP (Kaplan et al. 2005).
Timeframe
Another important vocabulary we need to have a basic
understanding of is about the two epochs. Geological epochs are geologic stratifications/timescales
involving different rock layers that form the Earth’s crust; the significance
of which is the present and last epochs provided many fossil finds that helps
in the understanding of the peopling of the world. The Pleistocene epoch spans
approximately 1.6 million BP to 10,000 BP. The next epoch is the Holocene and
spans up to the present time. The last two glacial maxima that happened in the
late Pleistocene and early Holocene may have played a significant role in the
peopling of the world.
Models of Migration in Southeast Asia
As scientists have explained, there are at least two great
migrations to the Philippines; the Itas and the Malay speakers. Gaillard and Mallari compiled the
various theories behind the peopling of the Philippines and of course it
touched on the surrounding areas within Southeast Asia. From what I observed,
the PASNP may support Manuel’s and Bellwood’s theories where the origins of the
Malay speakers may have been from mainland South China; more specifically, I
believe we are from Southwest China.
Ita ang Unang Tao sa Luson, Bisaya, at Mindanao
Itas are the first people to settle Luson, Bisaya, &
Mindanao
The Itas (Negritos)
were the first to settle Island Southeast Asia (ISEA). The famous Tabon Man
was discovered by Dr. Robert B. Fox in 1962 in the Tabon Caves of Palawan
island is one proof; it was dated at 22.5K BP. Although Scott states in his book that
the Tabon Man is not Ita I believe
the opposite is true. My reasoning is simply by process of elimination; all of
the archeological findings that links to the Austronesian speaking people
(Nusantao) in ISEA have never been more than 5.5K years old (Bellwood).
If not the Itas nor the Nusantao, who else can the Tabon Man be? Aside from the
Tabon Man, a new discovery by Dr. Armand Salvador B. Mijares of what may be the
oldest human fossil find in Southeast Asia called the Callao
Man; the Callao Man has been dated 67K BP and scientists describes part of
the bones found to be similar to modern Itas. There are also other sites from
other islands as shown in Table 1;
this table shows the various archaeological finds in Southeast Asia linked to
the Itas.
BTW: I call the Negritos, Tasmanians, Orang Asli (Negritos),
Australoids,
Australo-Melanesian, & Melanesoid as Ita
including all other group of people with the phenotype pigmented skin,
frizzy/curly hair and typically shorter in stature than the average East Asian
population. Ita is a term that my parent and my parents parents thought us who
these people were/are (at least in the Philippines at the time). This is what what
the Northern Itas call themselves also; the spelling may have evolved over
time. I have Ita blood myself and Itas are part of the fabric that makes a Malay.
Since there are no known land bridges that can connect
Palawan to mainland Luson (see satellite image from Google), we can infer that,
at least for the Itas in the Philippines (except Palawan), they have reached
the islands by means of a raft or some sort.
Figure 1: Snapshot of Philippines with the visible but submerged
land bridges connecting Palawan to the Sunda
shelf (from Google maps). The added highlights shows where humans would need a
raft of some sort to cross to the next island and reach Luson.
Table 1: List of Archaeological Finds Linked
to the Itas
Number
|
Date
(BP in thousand) |
Item
|
Site
|
Island
|
Country
|
Reference
|
Remarks
|
1
|
65.7
|
human third metatarsal
bone
|
Callao Cave
|
Luson
|
Philippines
|
Mijares et al. 2010
|
"Negrito"
|
2
|
40
|
deep skull
|
Niah Cave
|
Kalamintan
|
Malaysia
|
Kennedy 1977
|
"Tasmanians"
|
3
|
37
|
human tibia
|
Tabon Cave
|
Palawan
|
Philippines
|
Détroit et al. 2004, Fox
1970
|
"Melanesoid"
|
4
|
25.5
|
flaked artefacts and
charcoal
|
Callao Cave
|
Luson
|
Philippines
|
Mijares 2007, 2008
|
|
5
|
22
|
charcoal
|
Tabon Cave
|
Palawan
|
Philippines
|
Fox 1970
|
|
6
|
14.5
|
frontal bone
|
Tabon Cave
|
Palawan
|
Philippines
|
Dizon et al. 2002, Fox
1970
|
|
7
|
13.9
|
small flake assemblage
|
Ille Cave
|
Palawan
|
Philippines
|
Lewis et al. 2008
|
|
8
|
10.7
|
projectile points made
of bone and stingray spine
|
Niah Cave
|
Kalamintan
|
Malaysia
|
Barton et al. 2009
|
|
9
|
10
|
twenty-seven burial
remains
|
Gua Cha
|
Peninsular
|
Malaysia
|
Sieveking 1954, Adi 1985
|
"Melanesian"
|
10
|
10
|
male skeleton
|
Gua Gunung Runtuh
|
Peninsular
|
Malaysia
|
Zuraina 1994
|
"Australo-Melanesian"
|
11
|
7.5
|
twelve disturbed
skeletons
|
Sukajadi Pasar
|
Sumatra
|
Indonesia
|
Budhisampurno 1985
|
"Australo-Melanesian"
|
12
|
6.5
|
burials
|
Moh Khiew Cave
|
Peninsular
|
Malaysia
|
"Australo-Melanesian"
|
|
13
|
6.5
|
red painted bones, two
skulls
|
Wajak
|
Java
|
Indonesia
|
Dubois 1890
|
"Australo-Melanesian"
?
|
There are many surprising results regarding the Itas from a
previous blog
which I will expand here. First, there seems to be at least four unique Ita
populations in Southeast Asia.
1.
Orang Asli (Malaysian Itas: Kensui and Jehai)
2.
Ati Ita (Philippine Itas: Ayta, Ati, Agta, &
Iraya, North Ita)
3.
Mamanwa Ita (Philippine Ita, South Ita)
4.
Papuan
Figure 2: PC1 vs PC2
Plot (Zoomed)
These separations are demonstrated through the genetic
distance produced by Admixture, the correlation analysis, principal component
analysis and dendrogram. These large Ita separation is likely a very long period
of separation from each other. It is odd though that the obvious phenotypes did
not change much (pigmented skin and curly/frizzy hair – another topic for
another blog J ).
Initially, the Itas populated Southeast Asia including ISEA through land
bridges that appeared as an effect of ice ages. These land bridges lasted for a
very long time since population movements are not as quick as it is today;
we’re talking about thousands of years. Then later, the sea level rose and the
land bridges disappeared to where they are today. Since the Itas and most
people in the world did not have the technology to travel long distance by sea;
the genetic separation began and since the genetic distances are large, it must
have been thousands of years (long period).
I have updated the dendrogram from the previous blog using “complete” method. The “ward” method gave results inconsistent with the Fst table. I have also added some cluster box equal to 9, representing the 9 cluster populations.
I have updated the dendrogram from the previous blog using “complete” method. The “ward” method gave results inconsistent with the Fst table. I have also added some cluster box equal to 9, representing the 9 cluster populations.
Figure 3: PASNP Dendrogram (K=19)
The same can be said with the separation for the two groups
of Itas in the Philippines, the Mamanwa and North Itas. We can probably deduce
from this that the separation of the two Philippine Ita populations was due to
at least two major island groups that formed the Philippines during those ice
ages. If we look carefully at the Philippine map including the seabed, you can
almost make out at least two island groups. The Luzon – North Bisaya island and
the South Bisaya - Mindanao island. Again, these long period of physical
separation probably also caused the large genetic distance.
It’s interesting that the Papuans and Atis are close to each
other; I would have expected the Atis and Mamanwas would be closer due to
proximity. Perhaps the Mamanwas had a “bottle neck” founder populations similar
to the Mlabri, meaning, the founders of the Mamanwa before the separation came
from a small group of the bigger Ita group (bottle neck).
Figure 4: Ita
Admixture
The Mamanwa and the Ati Itas have significant admixture with
each other (Figure
5).
Mamanwa also have admixture with the 2nd group of migrants, the Malay
speakers; it shows an admixture range from 1.2% to 1.5% for the Ilokano,
Bisaya, & Tagalog samples while the Manobo (Mindanao Nusantao) clearly
admixed with Mamanwa at a higher percentage, 6.6%. The Ati Itas & Mamanwa
gene is present (albeit small amount) with all the countries in Southeast Asia
(Indonesia, Malaysia, Thailand, South China, Indian) in the PASNP data. This gene
presence is probably proof that they have once lived among the mainland East
Asians – Mon-Khmer, Nusantao, Tai-Kadai, & Sino-Tibetan, at the least and
South Asians (Indians). Note that there is a paper out there shows the South
Indians (Dravada speakers) to be another Ita group. (Vedoid) but the 4 Ita
groups in Southeast Asia are definitely distinct from the ancient Dravada
speakers.
Figure 5: Mamanwa Gene Percentage
Figure 6: Mamanwa Gene Prevalence
Figure 7: Ati Gene Percentage
Figure 8: Ati Gene
Prevalence
Figure 9 & Figure 10 bring in some inferences. The Ati & Mamanwa groups have only recently admixed with the Malay speakers (Nusantao). This is likely since the archaeological evidence of Malay settlements to ISEA are less than 5.5K BP. The significant Papuan presence in the Ati samples is a surprise. As mentioned, the four Ita groups have large separation. If it is true then the Papuan content is of recent admixture. Were the Papuans and/or Atis able to develop maritime technology (sea worthy ships)? The other possibility is that the Ati’s were the founder source for the Papuans (and perhaps the Mamanwas); given the relatively greater Ati diversity. Note the Mamanwas has 1.1% Papuan content. The Papuans, on the other hand, has 99.2% Papuan, 0.5% Ati, & 0.3% Mamanwa. Whatever the possibilities are, the Papuans, Mamanwas & Atis have significant interactions in Luson, Bisaya, & Mindanao.
Note: Although percentage less than 0.25% maybe be a margin
of error in admixture analysis, I would not completely dismiss these results
since we are only comparing 55,000 SNPs compared to the millions unidentified.
For the moment, I will most likely not explore percentage less than 0.25%.
Figure 9: Mamanwa Admixture
Figure 10: Ati Admixture
Figure 11:
Papuan Gene Percentage
Figure 12:
Papuan Gene Prevalence
Figure 13:
Malaysia Ita Gene Prevalence
Figure 14:
Malaysian Ita Admixture
References
1. Yang X, Xu
S, The HUGO Pan-Asian SNP Consortium (2011) Identification of Close Relatives
in the HUGO Pan-Asian SNP Database. PLoS ONE 6(12): e29502.
doi:10.1371/journal.pone.0029502
2. D.H.
Alexander, J. Novembre, and K. Lange. Fast model-based estimation of ancestry
in unrelated individuals. Genome Research, 19:1655–1664, 2009
3. H. Zhou,
D. H. Alexander, and K. Lange. A quasi-Newton method for accelerating the
convergence of iterative optimization algorithms. Statistics and Computing,
2009.
4. Alexander
D. H., Lange K. (2011). Enhancements to the ADMIXTURE algorithm for individual
ancestry estimation. BMC Bioinformatics 12:246. doi: 10.1186/1471-2105-12-246.
5. Purcell S,
Neale B, Todd-Brown K, Thomas L, Ferreira MAR, Bender D, Maller J, Sklar P, de
Bakker PIW, Daly MJ & Sham PC (2007) PLINK: a toolset for whole-genome
association and population-based linkage analysis. American Journal of Human
Genetics, 81.
6. Greenhill,
S.J., Blust. R, & Gray, R.D. (2008). The Austronesian Basic Vocabulary
Database: From Bioinformatics to Lexomics. Evolutionary Bioinformatics,
4:271-283.
7. Mijares,
A.S.B. et al. 2010. New evidence for a 67,000-year-old human presence at Callao
Cave , Luzon , Philippines. Journal of Human Evolution, 59:123-132.
doi:10.1016/j.jhevol.2010.04.008.
8. Mijares,
A.S.B.2007. The Late Pleistocene to Early Holocene For-agers of Northern Luzon.
Bulletin of the Indo-Pacific Prehistoric Association 28:99-107.
9. Sagart, L.
(2002). Sino-Tibeto-Austronesian: An Updated and Improved Argument. BMC
Bioinformatics 12:246. doi: 10.1186/1471-2105-12-246.
10. Gaillard, J. C. and Mallari,
J. P. (2004), The peopling of the Philippines: A cartographic synthesis, Hukay:
Journal of the University of the Philippines Archaeological Studies Program 6.
11. Mijares, A.S.B. 2008. The
Peñablanca Flake Tools: An Unchanging Technology? Hukay 12:13-34.
12. Mijares, A.S.B. et al. 2010.
New evidence for a 67,000-year-old human presence at Callao Cave , Luzon ,
Philippines. Journal of Human Evolution, 59:123-132.
doi:10.1016/j.jhevol.2010.04.008.
13. Dizon, E.Z. et al. 2002.
Notes on the Morphology and Age of the Tabon Cave Fossil Homo Sapiens. Current
Anthropology 43:660- 666.
14. Détroit, F. 2002. Origine
et évolution des Homo sapiens en Asie du Sud-Est: Descriptions et analyses
morphomé-triques de nouveaux fossiles. PhD thesis, Paris, France: Muséum
national d'Histoire naturelle.
15. Détroit, F. et al. 2004.
Upper Pleistocene Homo sapiens from Tabon cave (Palawan, the Philippines). Human
Paleontology and Prehistory 3:705–712.
16. Fox, R.B. 1970. The Tabon
Caves. Monograph of the National Museum of the Philippines. No. 1. Manila.
17. Barton, H., Piper, P.J.,
Rabett, R., and Reeds, I., 2009. Com-posite hunting technologies from the
Terminal Pleisto-cene and Early Holocene, Niah Cave, Borneo. Journal of
Archaeological Science 36:1708–1714.
18. Kaplan, M. R. et al. (2005).
Cosmogenic nuclide chronology of pre-last glacial maximum moraines at Lago
Buenos Aires, 468S, Argentina. Science Direct Quaternary Research 63
(2005) 301 – 315.
19. Kennedy, K. A. R. 1977. The
deep skull of Niah. AP 20:32-50.
20. Brothwell, D. R. 1960. Upper
Pleistocene human skull from Niah Caves, Sarawak. SMJ 9:323-349.
21. Lews, H et al. 2008. Terminal
Pleistocene to mid-Holocene occupation and an early cremation burial at Ille
Cave, Palawan, Philippines, Antiquity Volume: 82 Number: 316 Page:
318–335
22. Sieveking, G. de G. 1954.
Excavations at Gua Cha, Kelantan 1954. Part 1. FMJ 1 and 2:75-143.
23. Adi Haji Taha. 1985. The
re-excavation of the rockshelter of Gua Cha, Ulu Kelantan, West Malaysia. FMJ
30.
24. Zuraina Majid. ed. 1994. The
Excavation of Gua Gunung Runtuh. Malaysia: Department of Museums and
Antiquity.
25. Budhisampurno, S. 1985.
Kerangka manusia dari Bukit Kelambai Stabat, Sumatera Utara. Pertemuan
Ilmiah Arkeologi III, 955-984. Jakarta: Pusat Penelitian Arkeologi
Nasiona1.
26. Solheim, Wilhelm G.
Archaeology and culture in Southeast Asia : unraveling the Nusantao, (revised
edition), Diliman, Quezon City : University of the Philippines Press, 2006.
27. Purcell S, Neale B,
Todd-Brown K, Thomas L, Ferreira MAR, Bender D, Maller J, Sklar P, de Bakker
PIW, Daly MJ & Sham PC (2007) PLINK: a toolset for whole-genome association
and population-based linkage analysis. American Journal of Human Genetics, 81.