Category Archives: Human Evolution

Nepal in 1950s

Nepal is a small but ethno-linguistically rich Himalayan country that consists of eight of the world’s tallest mountains. Despite being small, Nepal is home to over one hundred languages. Where did these people originate? What are their histories? Unfortunately, due to scanty archeological and historical data, we do not know much about the Nepali linguistic communities.

Understanding population distribution i.e., where people live may tell us important things about origins and histories of a particular population. Basically, dense localization of a population in a particular area may suggest the population’s historical territory. Similarly, population spread may indicate migratory patterns of certain populations. If multiple populations harbor the same area, it is likely that gene flow between such populations may have occurred in the past.

Thus, to learn about the histories of different Nepali language communities, I looked at the census data from 1952-54, which is the first reliable census of Nepal. I obtained the data, formatted it, and cleaned it up a little bit.For this census, Nepal was divided into 9 census regions and 67 census districts (Fig.1). Although data for district level is available, I will focus on the regional data for this article.


Figure 1: Nine census regions in first Nepali census (1952-54 A.D.)

According to the census data, there were 8,473,478 people native to the 28,770 villages and cities in Nepal. Only five cities had more than 5000 inhabitants: Kathmandu (107K), Lalitpur (42K), Bhaktapur (32K), Nepalganj (11K), and Birganj (10K). Interestingly, Thimi, a town between Lalitpur, Kathmandu, and Bhaktapur also had 8.7K people. Migration rate, defined as people not present in their ancestral homes for six months or more, was negligible: 2.6% for the entire country and between 0.06-4.3% for the nine census regions. This makes sense because Nepal was very remote until recently. The first highway was constructed in 1960s before which traveling was probably very difficult, therefore rare. Closed to the western world until 1950, first available reports have also described Nepal as remote and rural and difficult to travel.

The negligible migration rates indicate that most Nepalis lived in their ancestral villages. Therefore, this census data may be useful in understanding the historical population structures within Nepal. Hence, I first looked at population density in each census region (Fig, 2).


Figure 2: Population density in the nine census regions in 1952-54

In the first glance, most populous region in Nepal was Western Hills and the least populous was Western Inner Terai. However, after accounting for geographical area, Kathmandu valley, which consists of three towns: Kathmandu, Bhaktapur, and Lalitpur, was remarkably the most populous region within Nepal consisting of 5% of the entire population. Around 45% Nepalis lived east of Kathmandu valley, Western Hills comprised of 40% of the population, and 61% of the Nepali populations lived in the Hills (Eastern and Western Hills combined). The least populated region in the country was Far-Western Terai, likely because it was covered with dense malaria infested jungles.



Figure 3: Population size of different ethnolinguistic communities within Nepal in 1950s

From the data, major language groups appear to be Nepali, Maithili, Tamang (Lama), Newari, Tharu, Magar, Rai, and Limbu. Although currently over 100 languages are recognized in Nepal, in the 1950 Census reported around 36 language groups (Fig.3), probably in an effort to not contradict Prithvi Narayan Shah’s Divyopadesh  in which he has proclaimed that Nepal is a common ground of 4 varnas and 36 jaats. Many of the smaller language groups in Terai have been lumped into “Pradesh dialects.” Also, several of the High Himalayan languages recognized today are missing. Because the census was conducted by traditional revenue collectors, known as  jimmewals and patwaris, perhaps the Rana government thought that the burden of visiting the remote High Himalaya was not worth the negligible revenues it would extract from its inhabitants. Therefore, it is reasonable to assume that these populations were not included in the first Nepali census of 1952-54.

My ultimate goal was to find clues about population histories of different ethnolinguistic groups within Nepal. Therefore, I used the “mother tongue” data to first see if I can learn anything about where different language communities lived in 1950s.



Figure 4: Ethnolinguistic diversity within Nepal in 1950

Figure 4 shows what proportion of population in each census region is contributed by which language community. For example, about 55% of population in Kathmandu were Newar, 40% were Nepali speakers, and the remaining 5% were Tamang. Although considered natives of Kathmandy valley, appreciable proportions of Newars were present outside of Kathmandu valley in Central Terai (5%) and Eastern Hills (4%). Newars were absent in all Terai regions.

The census clearly shows that Terai was populated by various non-Nepali speakers. Even in 1950s, it is clear that Nepali speakers were widespread in Nepali Hills and Inner Terai, but were also virtually absent (<5%) from all of the Terai (Fig.4). Given the low migration rates, it is likely that the populations that lived in certain parts of Terai in 1950 were native to that region. For example, the majority of populations in West-Inner Terai (57%) and Far-Western Terai (60%) were Tharu, a tribe that is indigenous to dense, malaria-infested, impenetrable jungles, also known as chaar-kose jaadi that decorated Terai until very recently. Indeed,  Danagaura Tharu (Banke, Bardiya, Dang, Surkhet), Kathariya Tharu (Kailali), and Rana Tharu (Kailali and Kanchanpur) are indigenous to FW Terai. Tharu presence is also strong in  Mid-Western Terai (20%) and Central Inner Terai (12%). Indeed, Chitawania Tharu are known to be indigenous to Chitwan, Bara, Persa in Center Inner Terai. The presence of Tharu is appreciable as well in East Inner Terai (6% of the population in Sindhuli and Udayapur), perhaps due to large populations of Kochila Tharu in this region. They are virtually absent in Kathmandu valley and in the Hills but interestingly, also in the Eastern Terai, which was mostly populated by Maithili speakers, perhaps because this region was once the capital of an ancient Maithili kingdom of Videha.

Tamang and Magar communities were widespread in Eastern as well as Central Nepal. Surprisingly, 33% of Nepalis in Central Inner Terai (Chitawan, Chisapani Garhi, and Nawalpur) were Tamang, although Tamangs were also present in Eastern hills and perhaps even in the high-altitude regions in the East. After Nepali and Tamang speakers, Rai (13%) and Limbu (8%) were the most populous groups in the Eastern Hills whereas  Magar were the third most populous in East-Inner Terai (12%).

Although this data indicates that Eastern Nepal was more diverse than Western Nepal, it is biased against the smaller language communities. For example, almost all of the 14,261 Chepang lived in the Central Inner Terai but they only comprised 6% of the population. Many other language communities have much smaller population sizes (Fig.3). Hence, to know the whereabouts of smaller language communities, I asked what proportions of speakers lived in each census region. In other words, I asked how each language group was distributed across different census regions (Fig.5).


Fig 5: Distribution of language families within Nepal in 1950

This figure clearly shows that many smaller language communities are localized to a particular region, especially in the Hills and Terai of the East. About 60% of Nepali speakers were present in Western Hills, indicating that Nepali speakers were originally residents of Western Hills and later spread rapidly to comprise the majority of populations in many other census regions (Fig 3). Although this is consistent with previous reports of rapid Khas migrations within Nepal, it is important to realize that this migration must have happened steadily over several generations because migration rate throughout the country was very low.

Eastern Hills appear to be very diverse along with Eastern Terai.  Many smaller language communities such as Jirel, Thami, and Sunuwar appear to be residents of Eastern Hills. Although Maithili is the dominant population in Eastern Inner Terai, Jhangar, Dhimal, Bhojpuri, Rajbanshi, and Satar also appear to be restricted to this region. It would be interesting to see when different populations arrived in this region of Nepal and whether any gene flow among these populations have occurred.

Also interesting is the Majwari population, which is present discontinuously in Eastern Terai and  Mid-Western Terai. Who are the Majwari peoples? How and why they moved within Nepal remains to be understood. Similarly, Sherpa seem to have two distinct populations: a strong presence in Eastern Hills and a moderate one in Western Hills. Danuwar also appear to have spread from Eastern to Central Nepal.

This data has shown that smaller language communities in Nepal have historically localized to particular regions whereas larger populations have moved around. However, there are certain populations that present in Eastern and Western Nepal but not in the middle. When did these populations migrate into separate regions? Given migration was negligible in 1950s, did these populations migrated in ancient times? Did they originate from the same ancestral population? How long ago they split? These are some interesting questions that need further work.



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Bonobo toolmaking hints glimpses of “cutting edge” stone age technology

This is really cool as human ancestors, many millions of years ago, my have started making tools in very similar fashion. Here is the Roffman et al. PNAS paper that describes the findings in detail.

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Modern human diseases and demographics

Tumultuous effects resulted and continue to result from the massive mixing of the world’s biota when European ships reconnected the American continent to the rest of the world.  Mann traced several of the cascading consequences of “the biggest ecological convulsion since the death of the dinosaurs.”
The first momentous change came from microbial exchange—20 lethal diseases came from Europe to the Americas while only one (syphilis) went the other way.  North America, which had been largely cleared by natives with fire and agriculture, reforested when two-thirds to 95% of the native inhabitants died from European diseases—”the greatest demographic catastrophe in human history.”  That huge reforesting drew down atmospheric carbon dioxide and Europe’s “Little Ice Age” (1550-1800) apparently resulted.
Meanwhile the mountain of silver at Potosí, Bolivia, vastly enriched Europe, which “went shopping” worldwide.  Trading ships coursed the world’s oceans.  One artifact picked up from Peru was the potato—a single variety of the  6,000 available.  When potatoes in Europe turned out to provide four times the amount of food per acre as wheat, the previously routine famines came to an end, population soared, governments became more stable, and they began building global empires.  After 1843 guano shipped by the ton from coastal Peru for fertilizer introduced high-input agriculture.  In Ireland 40% of the exploding population ate only potatoes.  Around 1844 a potato blight arrived from Mexico, and a million Irish died in the Great Famine and a million more emigrated.
In China, which has no large lakes and only two major rivers, agriculture had been limited to two wet regions where rice could be grown.  Two imports from America—maize and sweet potato—could be farmed in dry lands.  As in Europe, population went up.  Vast areas were terraced as Han farmers pushed westward as far as the Mongolian desert.  In heavy rains the terraces melted into the streams, and silt built up in the lowlands, elevating the rivers as much as 40 feet above the surrounding terrain, so when they flooded, millions died.  “A Katrina per month for 100 years,” as one Chinese meteorologist described it.  The constant calamities weakened the government, and China became ripe for foreign colonial takeover.
In America two imported diseases—malaria and yellow fever—were selective in who they killed.  Europeans died in huge numbers, but Africans were one-tenth as susceptible, and so slavery replaced traditional indentured servitude in all the warm regions that favored mosquito-borne diseases.  As one result, four times as many Africans as Europeans crossed the Atlantic and began mixing with the remaining native Americans, giving rise to an endless variety of racial blends and accompanying vitality throughout the Americas.
During the Q & A, Mann described a potential fresh eco-convulsion-in-waiting.  “There is an area in southeast Asia roughly the size of Great Britain that is a single giant rubber plantation.”  Where rubber trees originally came from in the Amazon there is now a rubber tree leaf-blight that is starting to spread in Asia.  “You could lose all the rubber trees in three to six months.  It would be the biggest deforestation in a long time.”  The entire auto industry, he added, depends on just-in-time delivery of rubber.
Stuart Brand’s summary of Charles C. Mann’s talk at The Longnow Foundation in April 2012. I decided to post it because it is one of the most eloquently articulated account of the modern history of Homo sapiens.

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Another example of ERV’s role in evolution

To end a royal dynasty, one has to eliminate its generals: this was the lesson of a Chinese movie I once watched in Netflix. Similar strategy is adopted by ERVs.
In a recent Plos Biology article (click here for a good summary for general audience) the authors identify MAVS, a protein produced by mitochondria (the general) that ignites immune response to protect the human cell (the Royalty) from Hepatitis-C virus (HCV). Three unrelated primates have the exact same non-synonymous mutation in the MAVS gene that  potentially alters the protein’s structure making it untouchable by the HCV particles. Unfortunately, humans, the primary host of HCV, do not have that mutation thus are relatively easily conquered by HCV. Sucks!
VERY INTERESTING is the presence of that same mutation in three different species: the authors apparently conclude it is a convergent evolution. However, this finding is in stark contrast with studies in yeast where convergence occurred at genic and network level but not at SNP level. Also, population genetics theories also find it very unlikely. Think about it, what is the probability that exactly same mutation would occur in three species branch AND SNP gets selected in all three branches? MINISCULE.
Could it be more plausible that the particular mutation existed in low frequencies in the common ancestor of all the primates and was readily available in all three branches at the time HCV like virus was active and quickly got fixed in the population? That particular virus probably did not infect humans (and other primates that do not have them) so they lost the mutaiton due to drift. Just a thought…

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Could Rautes, Kusundas, Chepangs, Rajis or Tharus be the first peoples to colonize the Himalayas 7000 years ago?

Rautes: The last nomads of Nepal

This picture belongs to Kishore K. Sharma, an awesome Nepali photographer. Please do visit his blog by clicking on this picture to view more pictures of the Rautes.

History of Nepal, as taught in academic institutions, starts with Gopalavamshis, the so-called first rulers of Nepal, followed by Mahispalavamshis, Kiratis, Licchavis, Mallas, and Shahs in that order. However it only represents the political history of Nepal at its best. To understand history of Nepal in its completeness, one must learn about the history of the peoples of Nepal.

Human inhabitation of the Himalayan foothills, known as present day Nepal, predates the dawn of civilization and the Gopalavamshis because prehistoric stone tools of “Patu industry,” a non-agricultural Mesothilic culture unique to Nepal were recovered in Central Nepal[1]. Two distinct types of tools, the Patu tools resembling the 10-12 thousand years old Hoabinhian culture and another resembling 10-30 thousand years old culture in India highlight three important points about ancient Nepali history: first, modern day Nepal has been inhabited by humans since the Pleistocene; second, Nepal has been cosmopolitan even in the Mesolithic harboring Indian and South East Asian cultures, and finally, the Patu people had an unique cultural identity by the Mesolithic.

But what happened to the Patu people? It is curious that a few nomadic hunter-gatherer tribes live/until recently lived the Mesolithic lifestyle in central Nepal, where the “Patu industry” once existed. Could they be the descendants of the Mesothilic humans that developed the first Himalayan culture?

Kusundas (aka Myahak, Ban Rajas) and Chepangs (aka Prajas) are one of the highly marginalized tribes in Nepal. Until a few decades ago both these tribes were nomadic hunter-gatherers. With forests gone, Kusundas were forced to desert their nomadic life and enter villages, which caused annihilation of their culture, traditions, and languages. Only a few Kusundas today, speak their native language. Like the Kusundas, Chepangs were also nomadic hunters and gatherers in central Nepal. Destruction of forests has forced Chepangs to adopt a semi-nomadic life in the non-yielding slopes of the Mahabharat range.

In addition to their hunter-gatherer lifestyles, linguistic and anthropological evidence suggest that Kusundas and Chepangs have been living in central Nepal since ancient times. Both the Kusundas and the Chepangs were officially first reported by B.H. Hodgson, a British naturalist and ethnologist in mid-nineteenth century, as “broken tribes” living nearly “in a state of nature” and carrying bows and arrows with no relationship with the rest of the “civilized races” of the country[2]. Later CJF Forbes found more plausible relationship between Chepangs and Khyens (Kiiyen) and Kumis of Arakan hills in Burma (Myanmar) and even concluded that Chepangs may have entered Nepal from the east [3]. Unlike Chepang, Kusunda language is difficult to classify as it similarities with various unrelated language groups such as Austro-Asiatic (Munda)[4], Tibeto-Burman, and even Indo-Pacific[5]. It is now widely recognized as a language isolate[6]: a language distinct from all other languages spoken in Nepal.

Although both Chepang and Kusunda languages seem to be unrelated to any other languages in Nepal, they appear to be linguistically closely related to each other (see Figure1). It is plausible that Chepangs and Kusundas have cohabited the Mahabharata hills and centuries of linguistic exchange may have resulted in their language similarities. Furthermore, anthropological evidence seems to corroborate the linguistic antiquity between these tribes, for example, both the Kusundas and the Chepangs have a folk legend according to which the Kusundas are the descendants of Kusa (thus the name Kusunda) and Chepangs are the descendants of Lava, both the sons of Rama and Sita of the Ramayana. Furthermore, interviews with Chepang traditional healers and medicine men revealed hundreds of plants used for diverse purposes and many of them were previously not documented.[7] The tremendous ethno-botanical knowledge of the Chepangs further substantiates their occupation of central Himalayas since ancient times for such knowledge of local flora can only be built with time. Hence, Kusundas and Chepangs, by virtue of their nomadic life styles and lack of linguistic affinities with any other languages of Nepal, may have inhabited the Himalayan foothills long before other ethnicities emigrated.

Recently, genomics has been used to infer the demographic histories of human populations throughout the world. Analysis of Kusunda genome in a recent issue of Science[8] supports some of the linguistic evidence and indicates that Kusundas are related to Tibeto-Burman speaking North East-Asian populations such as Hezhens, Oroqens and Mongolians but are not related to the Australian or Papuan Aborigines and virtually unrelated to any of the human populations from East or South Asia. Remarkably, a Kusunda specific genetic component is evident; however, without further analysis it is difficult to determine whether this component is due to long period of population isolation or due to ancient age of the population.

Genetic and linguistic evidence argues that Kusundas are possibly the most ancient of Nepali populations. They , may have come into contact with Mundas and Burmese in Eastern Himalayan foothills in ancient times. Words burrowed from these languages may have remained in Kusunda language to date. However, more work is needed to determine whether the Kusunda specific genetic components are a result of recent inbreeding due to population isolation or whether they are archaic genome components due to Kusundas’ antiquity in the Himalayan foothills.

Although it is tempting to crown Kusundas as the eldest peoples of Nepal, other nomadic/semi-nomadic tribes of central Nepal cannot be ignored. Genetic analysis of Chepangs may show that they have also cohabited the Mahabharata hills for centuries. It is also noteworthy that many other tribes along with Kusundas and Chepangs may have inhabited central Nepal since ancient times. For example, the Tharus may be descendants of inhabitants of the Terai since the Paleolithic. Tremendous ethnic and cultural diversity within Tharus that spread throughout the Terai region attest their occupation of the land for centuries. However, it is interesting that there is little linguistic similarity between the Tharus and the hunter-gatherers of central Nepal suggesting that there may have been very little interactions between the populations of the hills and that of the plains. Furthermore, Rautes that are still nomadic and Rajis that recently gave up nomadic lifestyle may have resided in central Nepal before the advent of agriculture. Many more ethnicities of Nepal may have inhabited the Himalayan foothills since ancient times but little is known about them. Hence, it is really important to investigate the history of all the peoples of Nepal for accurate presentation of Nepali history and their origins as such studies are also interesting from the perspectives of human evolution. Himalayas are believed to have acted as a barrier for gene flow between the Indian subcontinent and Central Asia. However, the fertile Himalayan foothills with diverse flora and fauna may have been a Mesolithic melting pot for migrants from both the sides of the Himalayas since Mesolithic times. Understanding the origins and demographic histories of present tribes of Nepal may reveal novel aspects of ancient human dynamics in Asia.

In summary, there is abundant evidence that present day Nepal was inhabited by humans since the Paleolithic and a culture unique to Nepal existed by Mesolithic. It is possible that hunter-gatherer populations currently residing in central Nepal, such as Kusundas, Chepangs, Rautes, and Rajis may be the descendents of the Patu people that developed the first culture of Nepal some 7000 years ago. There is a dire need for additional archeological, anthropological, linguistic, and genomic studies to understand the ancient history of Nepal accurately.

[2] Hodgson, B. H. (1848) J. Asiat. Soc. Bengal 17 , 73–78

[3] Forbes, C. J. F. (1877) Journal of the Royal Asiatic Society of Great Britain and Ireland, New Series, Vol. 9,No. 2,  pp. 421-424

[4] Reinhard, J. & Toba, T. (1970) A Preliminary Linguistic Analysis and Vocabulary of the Kusunda Language (Summer Institute of Linguistics, Kirtipur, Nepal).

[5] Whitehouse et al. (2004) Kusunda: An Indo-Pacific language in Nepal. PNAS Vol. 101,No. 15, pp. 5692-5695

[6] Watters, D. (2005) Notes on Kusunda grammar (a language isolate of Nepal). Kathmandu: National Foundation for the Development of Indigenous Nationalities.

[7] Rijal A. 2011. Surviving on knowledge: ethnobotany of Chepang community from midhills of Nepal. Ethnobotany Res Appl 9:181-215.

[8] Rasmussen, M. et al. (2011) An Aboriginal Australian Genome Reveals Separate Human Dispersals into Asia. Science Vol. 334, No. 6052, pp.94-98


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Who were the Neanderthals?

Neanderthals, man’s closest relatives have excited many scientists for decades. In the past there have been many hypothesis and myths about Neanderthals by virtue of which, they have been portrayed as barbaric hominins that lacked culture. However, recent reports suggest Neanderthals were culturally sophisticated hominins that interbred with humans outside Africa. Here, I attempt to congregate scientific papers that debunk the myths about Neandethals. This is a work in progress and any additional articles about Neanderthals from the readers is highly appreciated.

Listen to NPR podcast on Neanderthals vs. Humans (7:35 onwards in the podcast) that discusses human brain development.

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Sperm: The Evidence for Evolution?

“This is the first clear evidence that suggests our ability to produce sperm is very ancient, probably originating at the dawn of animal evolution 600 million years ago,” said Eugene Xu, assistant professor of obstetrics and gynecology at Feinberg. “This finding suggests that all animal sperm production likely comes from a common prototype.”

This week’s journal Nature Research Highlight section features an article originally published in PNAS that demonstrates that some species of promiscuous hermaphroditic flatworms have “a variety of sperm shapes”. The ejaculate containing sperms are sucked by these worms after sex and only those sperms that have “pair of long bristles emerging at the mid-point and a tail resembling a paint brush” can anchor themselves in “the female orifice after copulation, preventing the sperm from being sucked out.” This is one example of adaptive evolution in these worms to select for those sperms that can quickly implant themselves in the female reproductive system such that they have higher chances to produce a zygote.
Figure obtained from Nature

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