History of the Indian caste system
Indian society has consisted of thousands of endogamous clans and groups called jatis since ancient times. The Brahminical scriptures and texts tried to bring this diversity under a comprehensible scheme which hypothesised four idealised meta groups called varna. The first mention of the formal varna Indian caste system is in the famous Purush Sukta of the Rigveda, although it is the only mention in the entire body of the Vedas and has been decried as a much later, non-Vedic insertion by numerous Indologists like Max Muller and also by Ambedkar.
Possible genetic origin 
If we hold into account the popular theory of Eurasian landmass and its split, India was one of the chosen topographic point for migrating tribes and explorers, along with Persia and Mesopotamia. Indian subcontinent has strategic advantage in the sense of topography i.e. Himalayas to the north and the Indian oceans protecting the other sides. At the time when large tribes were still migrating, this tropical land was a good choice given that the occupations of the time were farming, fishing and such. As newer tribes entered the land, one or the other of those tribes may have dominated the other to submission. This trend is contemporaneous even in other parts of the world as well.
The Indian subcontinent has been politically active since at least last 5000 years. There are indigenous tribes mentioned in Mahabharata, such as the Nagas, that still inhabit the land. Accounts of travelers from Greece, China and Persia observed India to be a complex society with stratification at various levels. However, given such a long timeline, it is not possible to find empirical proof. Hence most conclusions about the origin of caste systems are inferences. The only possible conclusive study on the matter could be made through genetic studies.
The origins of the Jati system or caste system are lost in popular history and folklore. Many scholars believe that the modern Jatis represent ancient tribal and occupational affiliations that have evolved and specialised over time. A question had remained whether or not castes are genetically distinct, and whether genetic differences between groups might partly explain their origin. These genetic studies have so far failed to achieve a consensus, possibly because of the developing nature of genotyping science and technologies.
A 1995 study by Joanna L. Mountain et al. of Stanford University concluded that there was "no clear separation into three genetically distinct groups along caste lines", although "an inferred tree revealed some clustering according to caste affiliation".
A 2001 genetic study, led by Michael Bamshad of University of Utah, found that the genetic affinity of Indians to Europeans is proportionate to caste rank, the upper castes being most similar to Europeans, whereas lower castes are more like Asians. The researchers believe that the Indo-European speakers entered India from the Northwest, admixing with or displacing the proto-Dravidian speakers. Subsequently they may have established a caste system and placed themselves primarily in higher castes. The study concludes that the Indian castes "are most likely to be of proto-Asian origin with West Eurasian admixture resulting in rank-related and sex-specific differences in the genetic affinities of castes to Asians and Europeans.". Because the Indian samples for this study were taken from a single geographical area, it remains to be investigated whether its findings can be safely generalized.
A 2003 report by T. Kivisild et al. concluded that the "Indian tribal and caste populations derive largely from the same genetic heritage of Pleistocene southern and western Asians and have received limited gene flow from external regions since the Holocene." These scientists conclude that their observation does not refute the existence of genetic footprints in India from central Asia, eastern Europe or elsewhere. The genetic influence is higher in northwest regions of India, than other parts. Further, such broad estimates, according to these scientists are preliminary, at best. It will take larger sample sizes, more populations, and increased molecular resolution to determine the impact of historic gene flows to India.
A 2006 genetic study by the National Institute of Biologicals in India, testing a sample of men from 32 tribal and 45 caste groups, concluded that the Indians have acquired very few genes from Indo-European speakers. The conclusion of this study has been disputed by later studies.
According to a 2006 study by Ismail Thanseem et al. of Centre for Cellular and Molecular Biology (India) "the vast majority (>98%) of the Indian maternal gene pool, consisting of Indo-European and Dravidian speakers, is genetically more or less uniform", while the invasions after the late Pleistocene settlement might have been mostly male-mediated. The study concluded that the "lower caste groups might have originated with the hierarchical divisions that arose within the tribal groups with the spread of Neolithic agriculturalists, much earlier than the arrival of Aryan speakers", and "the Indo-Europeans established themselves as upper castes among this already developed caste-like class structure within the tribes." The study indicated that the Indian caste system may have its roots much before the arrival of the Indo-Aryan immigrants; a rudimentary version of the caste system may have emerged with the shift towards cultivation and settlements, and the divisions may have become more well-defined and intensified with the arrival of Indo-Aryans.
A 2009 article published in Nature finds strong evidence for at least two ancient populations in India, genetically divergent, that are ancestral to most Indians today. One, the Ancestral North Indians, who are genetically close to Middle Easterners, Central Asians, and Europeans, whereas the other, the Ancestral South Indians, who are genetically distinct from Ancestral North Indians and East Asians as they are from each other. The study observes that genetic markers suggest endogamy within population clusters was prevalent in various Indian kingdoms over time. The report includes a novel method to estimate ancestry without accurate ancestral populations. With this method, the scientists show that Ancestral North Indians ancestry ranges from 39–71% in most Indian groups, and is higher in traditionally upper caste and Indo-European language speakers. Groups with only Ancestral South Indians ancestry may no longer exist in mainland India due to genetic pool mixing. However, the indigenous Andaman Islanders are unique in being Ancestral South Indians-related groups without Ancestral North Indians ancestry.
A 2010 review claims that there are at least four population groups in diverse India. Other than Ancestral North Indians and Ancestral South Indians, the population consists of Tibeto-Burman, Austro-Asiatic and Andamanese genetic pools suggesting human beings migrated into India from Africa, Eurasia, Tibet and southeast Asia. The review paper notes that studies so far were based on small sample sets for the diversity in India. With the availability of new genotyping technologies, future diversity studies encompassing a large number of populations, both tribals and castes, at the genome-wide level may help understand patterns of micro-evolution of populations in India. The caste system in India is possibly a complex intra-group and inter-group admix of interactions between various population groups.
Hindu scriptures 
The most ancient scriptures—the Shruti texts, or Vedas, place very little importance on the caste system, mentioning caste only sparingly and descriptively (i.e., not prescriptive). Indeed, the only verse in the Rigveda which mentions all four varnas is 10.90, the Purushasūkta. A hymn from the Rig Veda seems to indicate that one's caste is not necessarily determined by that of one's family:
Rig Veda 9.112.3—I am a bard, my father is a physician, my mother's job is to grind the corn.
In the Vedic period, there also seems to have been no discrimination against the Shudras on the issue of hearing the sacred words of the Vedas and fully participating in all religious rituals, something which became progressively restricted in the later times.
Later scriptures such as Bhagavad Gita and Manusmriti state that the four varnas are created by God. However, at the same time, the Gita says that one's varna is to be understood from one's personal qualities and one's karma (work), not one's birth. The Indian society honoured people on their achievements irrespective of their caste. For instance, Valmiki, once a low-caste robber, became a great sage and author of the epic Ramayana. Veda Vyasa, another respected sage and author of the monumental epic, the Mahabharata, was the son of a fisherwoman.
Manusmriti, dated between 200 BCE and 100 CE, contains some laws that codified the caste system. The Manu Smriti belongs to a class of books that are geared towards ethics, morals, and social conduct - not spirituality or religion.
Historical records 
A historical record of ancient North Indian society is provided by the Greek Megasthenes, who, in his Indika, described the society as being made up of "seven castes":
"The whole population of India is divided into seven castes, of which the first is formed by the collective body of the Philosophers, which in point of number is inferior to the other castes, but in point of dignity preeminent over all. For the philosophers, being exempted from all public duties, are neither the masters nor the servants of others. They are, however, engaged by private persons to offer the sacrifices due in lifetime, and to celebrate the obsequies of the dead: for they are believed to be most dear to the gods, and to be the most conversant with matters pertaining to Hades. In requital of such services they receive valuable gifts and privileges. To the people of India at large they also render great benefits, when, gathered together at the beginning of the year, they forewarn the assembled multitudes about droughts and wet weather, and also about propitious winds, and diseases, and other topics capable of profiting-the hearers. Thus the people and the sovereign, learning beforehand what is to happen, always make adequate provision against a coming deficiency, and never fail to prepare beforehand what will help in a time of need. The philosopher who errs in his predictions incurs no other penalty than obloquy, and he then observes silence for the rest of his life."
The other classes are also described by Arrian, in The Anabasis Alexandrae, Book VIII: Indica (2nd century CE) relying on the account of Megasthenes:
"Then next to these come the farmers, these being the most numerous class of Indians; they have no use for warlike arms or warlike deeds, but they till the land; and they pay the taxes to the kings and to the cities, such as are self-governing; and if there is internal war among the Indians, they may not touch these workers, and not even devastate the land itself; but some are making war and slaying all comers, and others close by are peacefully ploughing or gathering the fruits or shaking down apples or harvesting.
The third class of Indians are the herdsmen, sheep and cattle pastoralists, and these dwell neither by cities nor in the villages. They are nomads and get their living on the hillsides, and they pay taxes from their animals; they hunt also birds and wild game in the country.
The fourth class is of artisans and shopkeepers; these are workers, and pay tribute from their works, save such as make weapons of war; these are paid by the community. In this class are the shipwrights and sailors, who navigate the rivers.
The fifth class of Indians is the soldiers' class, next after the farmers in number; these have the greatest freedom and the most spirit. They practise military pursuits only. Their weapons others forge for them, and again others provide horses; others too serve in the camps, those who groom their horses and polish their weapons, guide the elephants, and keep in order and drive the chariots. They themselves, when there is need of war, go to war, but in time of peace they make merry; and they receive so much pay from the community that they can easily from their pay support others.
The sixth class of Indians are those called overseers. They oversee everything that goes on in the country or in the cities; and this they report to the king, where the Indians are governed by kings, or to the authorities, where they are independent. To these it is illegal to make any false report; nor was any Indian ever accused of such falsification.
The seventh class is those who deliberate about the community together with the king, or, in such cities as are self-governing, with the authorities. In number this class is small, but in wisdom and uprightness it bears the palm from all others; from this class are selected their governors, district governors and deputies, custodians of the treasures, officers of army and navy, financial officers and overseers of agricultural works.
The same man may not practise two pursuits; nor change from one class into another, as to turn farmer from shepherd, or shepherd from artisan. It is only permitted to join the wise men out of any class; for their business is not an easy one, but of all most laborious."
Emergence of rigid caste structures 
Megasthenes, the Greek ambassador to Chandragupta Maurya's court in India classified people of India into seven classes: philosophers, peasants, herdsmen, craftsmen and traders, soldiers, government officials and councillors.
In its later stages, the caste system is said to have become rigid, and caste began to be inherited rather than acquired by merit. In the past, members of different castes would not partake in various activities, such as dining and religious gatherings, together. In addition, the performance of religious rites and rituals were restricted to Brahmins, who were the designated priesthood. The "Pandaram" priests are an example of an order of priests, based in Nepal and South India. The Pandaram maintain the same tradition as the Brahmin priests, including the use of the Sanskrit language (traditionally reserved for the Brahmins) for the rituals. While they are not generally as well trained as the Brahmin priests, they are highly respected within their community and are addressed with reverence.
According to the Manusmriti, every caste belongs to one of the four varnas (Brahmin, Kshtriya, Vaishya, and Shudra). However, there have been many disputes about the varna of many castes, such as castes being considered Kshatriya by some scholars, while described as Shudra by others. While texts such as the Manusmriti attempted to rationalize ambiguous castes by placing them in varna-sankaras (i.e. mixed varna), the fact remains that Indian society was, and is, composed of numerous geographically diversified but endogamous groups. With many occupational groups practicing endogamy within a particular region, as well as numerous sub-divisions within the four main castes, a more complex system of subcastes and jātis is evident. The jatis have broken up into clans like Agarwal, Iyer, etc.
Mobility across the castes 
The view of the caste system as "static and unchanging" has been disputed by many scholars. For instance, sociologists such as Bernard Buber and Marriott McKim describe how the perception of the caste system as a static and textual stratification has given way to the perception of the caste system as a more processual, empirical and contextual stratification. Other sociologists such as Y.B Damle have applied theoretical models to explain mobility and flexibility in the caste system in India. According to these scholars, groups of lower-caste individuals could seek to elevate the status of their caste by attempting to emulate the practices of higher castes.
The distinctions, particularly between the Brahmans and the other castes, were in theory sharper, but in practice it now appears that social restrictions were not so rigid. Brahmans often lived off the land and founded dynasties. Most of the groups claiming Kshatriya status had only recently acquired it. The conscious reference to being Kshatriya, a characteristic among Rajputs, is a noticeable feature in post-Gupta politics. The fact that many of these dynasties were of obscure origin suggests some social mobility: a person of any caste, having once acquired political power, could also acquire a genealogy connecting him with the traditional lineages and conferring Kshatriya status. A number of new castes, such as the Kayasthas (scribes) and Khatris (traders), are mentioned in the sources of this period. According to the Brahmanic sources, they originated from intercaste marriages, but this is clearly an attempt at rationalizing their rank in the hierarchy. Many of these new castes played a major role in society. The hierarchy of castes did not have a uniform distribution throughout the country.
According to some psychologists, mobility across broad caste lines may have been "minimal", though sub-castes (jatis) may change their social status over the generations by fission, re-location, and adoption of new rituals.
Sociologist M. N. Srinivas has also debated the question of rigidity in Caste. In an ethnographic study of the Coorgs of Karnataka, he observed considerable flexibility and mobility in their caste hierarchies. He asserts that the caste system is far from a rigid system in which the position of each component caste is fixed for all time. Movement has always been possible, and especially in the middle regions of the hierarchy. It was always possible for groups born into a lower caste to "rise to a higher position by adopting vegetarianism and teetotalism" i.e. adopt the customs of the higher castes. While theoretically "forbidden", the process was not uncommon in practice. The concept of sanskritization, or the adoption of upper-caste norms by the lower castes, addressed the actual complexity and fluidity of caste relations.
Historical examples of mobility in the Indian Caste System among Hindus have been researched. There is also precedent of certain Shudra families within the temples of the Shrivaishava sect in South India elevating their caste.
British rule 
The caste system had been a fascination of the British since their arrival in India. Coming from a society that was divided by class, the British attempted to equate the caste system to the class system. As late as 1937 Professor T. C. Hodson stated that: "Class and caste stand to each other in the relation of family to species. The general classification is by classes, the detailed one by castes. The former represents the external, the latter the internal view of the social organization."
Reform movements 
There have been cases of upper caste Hindus warming to the Dalits and Hindu priests, demoted to outcaste ranks, who continued practising the religion. An example of the latter was Dnyaneshwar, who was excommunicated from society in the 13th century, but continued to compose the Dnyaneshwari, a Dharmic commentary on the Bhagavad Gita. Other excommunicated Brahmins, such as Eknath, fought for the rights of untouchables during the Bhakti period. Historical examples of Dalit priests include Chokhamela in the 14th century, who was India's first recorded Dalit poet, Raidas, born into Dalit cobblers, and others. The 15th-century saint Ramananda also accepted all castes, including untouchables, into his fold. Most of these saints subscribed to the Bhakti movements in Hinduism during the medieval period that rejected casteism. Nandanar, a low-caste Hindu cleric, also rejected casteism and accepted Dalits.
Many movements in Hinduism have welcomed Dalits into their fold, the foremost being the Bhakti movements of the medieval period. Early Dalit politics involved many Hindu reform movements which arose primarily as a reaction to the tactics of Christian Missionaries in India and their attempts to mass-convert Dalits to Christianity under the allure of escaping the caste system (although there is Caste system among Indian Christians among large sections of Indian Christians).
In the 19th century, the Brahmo Samaj under Raja Ram Mohan Roy, actively campaigned against untouchability. The Arya Samaj founded by Swami Dayanand also renounced discrimination against Dalits. Sri Ramakrishna Paramahamsa founded the Ramakrishna Mission that participated in the emancipation of Dalits. Upper caste Hindus, such as Mannathu Padmanabhan also participated in movements to abolish Untouchability against Dalits, opening his family temple for Dalits to worship. While there always have been places for Dalits to worship, the first "upper-caste" temple to openly welcome Dalits into their fold was the Laxminarayan Temple in Wardha in the year 1928 (the move was spearheaded by reformer Jamnalal Bajaj). Also, the Satnami movement was founded by Guru Ghasidas, a Dalit himself. Other reformers, such as Mahatma Jyotirao Phule also worked for the emancipation of Dalits. Another example of Dalit emancipation was the Temple Entry Proclamation issued by the last Maharaja of Travancore in the Indian state of Kerala in the year 1936. The Maharaja proclaimed that "outcastes should not be denied the consolations and the solace of the Hindu faith". Even today, the Sri Padmanabhaswamy temple that first welcomed Dalits in the state of Kerala is revered by the Dalit Hindu community. The 1930s saw key struggles between Mahatma Gandhi and B.R. Ambedkar, most notably over whether Dalits would have separate electorates or joint electorates with reserved seats. The Indian National Congress was the only national organisation with a large Dalit following, but Gandhi failed to gain their commitment. Ambedkar, a Dalit himself, developed a deeper analysis of Untouchability, but lacked a workable political strategy: his conversion to Buddhism in 1956, along with millions of followers, highlighted the failure of his political endeavours. India's first Prime Minister, Jawaharlal Nehru, based on his own relationship with Dalit reformer Ambedkar, also spread information about the dire need to eradicate untouchability for the benefit of the Dalit community.
In more contemporary times, India has had an elected Dalit president, K. R. Narayanan, who has stated that he was well-treated in his community of largely upper-caste Hindus (24 July 2002). Another popular Harijan includes Babaji Palwankar Baloo, who joined the Hindu Mahasabha and was both a politician and a cricketer. He was an independence fighter. In addition, other Hindu groups have reached out to the Dalit community in an effort to reconcile with them, with productive results. On August 2006, Dalit activist Namdeo Dhasal engaged in dialogue with the Rashtriya Swayamsevak Sangh in an attempt to "bury the hatchet".
Also, the "Pandaram" are an order of Dravidian Tamil Hindu priests (a task traditionally reserved for the Brahmins) based largely in Nepal and parts of South India. These Pandaram priests maintain the same tradition as the Brahmin priests, including using Sanskrit for the rituals . They perform religious ceremonies from weddings to death rituals. They are highly respected within the Tamil community and are addressed reverentially. Also, Hindu temples are increasingly more receptive to Dalit priests, such as Suryavanshi Das, the Dalit priest of a notable temple in the midst of Patna, the capital of Bihar.
Discrimination against Hindu Dalits is on a slow but steady decline. The results of Bhakti Movements are clearly visible. Numerous Hindu Dalits have achieved affluence in society, although vast still remain poor irrespective of caste. In urban India, discrimination against Dalits is largely disappeared, but rural Dalits are struggling to elevate themselves. Government organizations and NGO's work to emancipate them from discrimination, and many Hindu organizations have spoken in their favor.
- Mountain, Joanna L.; J M Hebert, S Bhattacharyya, P A Underhill, C Ottolenghi, M Gadgil, and L L Cavalli-Sforza (April 2013). "Demographic history of India and mtDNA-sequence diversity". American Journal of Human Genetics 56 (4): 979–992. ISSN 0002-9297. PMC 1801212. PMID 7717409. Retrieved 2007-09-09.
- Bamshad, Michael; Kivisild T, Watkins WS, Dixon ME, Ricker CE, Rao BB, Naidu JM, Prasad BV, Reddy PG, Rasanayagam A, Papiha SS, Villems R, Redd AJ, Hammer MF, Nguyen SV, Carroll ML, Batzer MA, Jorde LB (June 2001). "Genetic Evidence on the Origins of Indian Caste Populations". Gnome Research 11 (6): 994–1004. doi:10.1101/gr.GR-1733RR. PMC 311057. PMID 11381027. Retrieved 2007-09-09.
- Basu, Analabha; Namita Mukherjee, Sangita Roy, Sanghamitra Sengupta, Sanat Banerjee, Madan Chakraborty, Badal Dey, Monami Roy, Bidyut Roy, Nitai P. Bhattacharyya, Susanta Roychoudhury and Partha P. Majumder (2003). "Ethnic India: A Genomic View, With Special Reference to Peopling and Structure". Gnome Research 13 (10): 2277–2290. doi:10.1101/gr.1413403. PMC 403703. PMID 14525929. Retrieved 2007-09-09.
- Kivisild, T.; S. Rootsi, M. Metspalu, S. Mastana, K. Kaldma, J. Parik, E. Metspalu, M. Adojaan, H.-V. Tolk, V. Stepanov, M. Gölge, E. Usanga, S. S. Papiha, C. Cinnioglu, R. King, L. Cavalli-Sforza, P. A. Underhill, and R. Villems (February 2003). "The Genetic Heritage of the Earliest Settlers Persists Both in Indian Tribal and Caste Populations". American Journal of Human Genetics 72 (2): 313–332. doi:10.1086/346068. PMC 379225. PMID 12536373. Retrieved 2007-09-09.
- Brian Handwerk (10 January 2006). "India Acquired Language, Not Genes, From West, Study Says". National Geographic News. Retrieved 2006-12-08.
- David Reich et al. (24 September 2009). "Reconstructing Indian population history". Nature 461 (7263): 489–494. doi:10.1038/nature08365. PMC 2842210. PMID 19779445.
- Thanseem, Ismail; Kumarasamy Thangaraj, Gyaneshwer Chaubey, Vijay Kumar Singh, Lakkakula VKS Bhaskar, B Mohan Reddy, Alla G Reddy, and Lalji Singh (August 2006). "Genetic affinities among the lower castes and tribal groups of India: inference from Y chromosome and mitochondrial DNA" (PDF). BMC Genetics 7: 42. doi:10.1186/1471-2156-7-42. PMC 1569435. PMID 16893451. Retrieved 2007-09-09.
- G.S. Mudur (1 January 2007). "Caste in the genes". The Telegraph. Calcutta. Retrieved 2007-08-31.
- Aryan-Dravidian divide a myth: Study, Times of India
- Majumdar (23 February 2010). "The Human Genetic History of South Asia: A Review". Current Biology 20: R184–R187. doi:10.1016/j.cub.2009.11.053. PMID 20178765.
- White Yajurveda 26.2
- Sabhlok, Prem. "Glimpses of Vedic Metaphysics". Page 21.
- Mgasthenes's Indika, see section 40.
- Nepal's Downtrodden,Hinduism Today
- Moffatt, Michael, An Untouchable Community in South India: Structure and Consensus. Man, New Series, Vol. 15, No. 1 (Mar., 1980), p. 208
- James Silverberg (November 1969). "Social Mobility in the Caste System in India: An Interdisciplinary Symposium". The American Journal of Sociology 75 (3): 443–444. JSTOR 2775721.
- "Govind Sadashiv Ghurye: Ghurye's Views about Indian Society" (PDF). Archived from the original on 26 February 2007. Retrieved 2007-05-04.
- "India." Encyclopædia Britannica. 2008. Encyclopædia Britannica Online. 6 June 2008
- Social Structure & Mobility in Economic Development, By Neil J. Smelser, Seymour Martin Lipset, Published 2005
- Srinivas, M.N, Religion and Society among the Coorgs of South India by MN Srinivas, Page 32 (Oxford, 1952)
- Caste in Modern India; And other essays: Page 48. (Media Promoters & Publishers Pvt. Ltd, Bombay; First Published: 1962, 11th Reprint: 1994)
- Mendelsohn, Oliver & Vicziany, Maria, "The Untouchables,Subordination, Poverty and the State in Modern India", Cambridge University Press, 1998
- K. R. Narayanan: Farewell address to the nation, 24 July 2002. Retrieved 24 February 2006.
- Dalit leader buries the hatchet with RSS, Sangh Parivar insider's perspective
- Dalit priest in temple of Buddha and Hanuman, Hindustan Times
- The Dharmic battle against Untouchability, Hindu Voice
- The International Dalit Solidarity Network: Dalits in India
- Caste in Medieval India: The Beginnings of a Reexamination
- Seventy-two Specimens of Castes in India Full-color hand-painted images of men and women of the various castes and religious and ethnic groups found in Madura, India in 1837 from the collection of the Beinecke Rare Book and Manuscript Library at Yale University