Come to­gether

With DNA adding to the slip­pery nar­ra­tives about the past; his­to­ri­ans, arche­ol­o­gists, and ge­neti­cists need to col­lab­o­rate if we are to take a less big­oted view of his­tory

Down to Earth - - CONTENTS - RAKESH KAL­SHIAN

His­to­ri­ans, ge­neti­cists and ar­chae­ol­o­gists have to col­lab­o­rate if his­tory is to be less big­oted

WHERE ARE you from? This cu­rios­ity, of­ten traded be­tween strangers in al­most all cul­tures, sig­ni­fies our abid­ing fas­ci­na­tion with ori­gins. What we be­lieve where we come from or who we are is a col­lage of fam­ily mem­o­ra­bilia like pho­to­graphs, di­aries and let­ters, cer­tifi­cates of birth and blood type, and of course mem­o­ries passed down the gen­er­a­tions. How­ever, if were to trace back our lines of de­scent, most of us would run into a foggy ter­rain past our grand­par­ents (how many of you know about the life worlds of your great grand­par­ents?). The pic­ture turns even grainier if you hap­pened to be an im­mi­grant, or adopted, or born to a sur­ro­gate mother, or even some­one with par­ents of mixed eth­nic­ity, caste, re­li­gion, or na­tion­al­ity.

A per­son’s lin­eage is like the Ma­tryoshka doll, with each nested doll car­ry­ing a story within a story of in­creas­ing com­plex­ity coloured by a sub­jec­tive in­ter­pre­ta­tion of sur­viv­ing ves­tiges of the past. If the small­est doll is the story of an in­di­vid­ual go­ing back to, say, three gen­er­a­tions, it is cir­cum­scribed by fat­ter dolls that tell grander, and of­ten fab­ri­cated, tales about her clan or com­mu­nity, about the re­gion or em­pire or na­tion, and fi­nally about the world, in that or­der.

In re­cent years, dna as wit­ness has added an­other twist to the al­ready com­pli­cated nar­ra­tives about the past. Read­ing his­tory through dna can be done in two ways. One, ex­tract it from the re­mains of the an­cient dead, re­con­struct it, and then see if it is re­lated to the liv­ing. Two, com­pare the dna of two or more liv­ing per­sons or pop­u­la­tions to see if they had a com­mon an­ces­tor. This is pos­si­ble be­cause the dna of all hu­mans con­tains just one spelling er­ror for ev­ery 1000 let­ters of the 3 billion-let­ter-long ge­netic Al­pha­bet. The more such er­rors (of which there are mil­lions) you share with an­other

per­son the more re­lated you are to him or her.

What makes ge­netic his­tory (as it is re­ferred to by some) dif­fer­ent, not to men­tion prob­lem­atic, is that un­like sci­en­tific tech­niques used by his­to­ri­ans and arche­ol­o­gists, such as car­bon dat­ing or re­mote sens­ing, dna clues are seen as mark­ers of iden­tity. Per­ceived as a more cred­i­ble fin­ger­print of by­gones, it is mak­ing bold claims about our pasts, in­di­vid­ual as well as col­lec­tive, that are of­ten at odds with how we have imag­ined them for long. Hence their pop­u­lar, not to say dan­ger­ous, ap­peal. Con­sider me­dia head­lines like “Bri­tain is more Ger­manic than it thinks”; “We Euro­peans are Asians”.

As Bri­tish ge­neti­cist Bryan Sykes, a pi­o­neer of an­cient dna re­search and founder of Ox­ford An­ces­tors, a com­pany that traces ances­try through dna, wrote in his best­selling Seven Daugh­ters of Eve: “Within the dna is writ­ten not only our his­to­ries as in­di­vid­u­als, but the whole his­tory of the hu­man race… Our dna does not fade like an an­cient parch­ment; it does not rust in the ground like the sword of a war­rior long dead. It is not eroded by wind or rain, nor re­duced to ruin by fire and earth­quake.”

In the early 1990s, the Amer­i­can ge­neti­cist Luigi Luca Cavalli-Sforza mounted the Hu­man Genome Di­ver­sity Project, an am­bi­tious at­tempt to re­con­struct the evo­lu­tion of hu­mans and lan­guage by col­lect­ing dna from across the world. The project, how­ever, was shelved, as indige­nous peo­ple feared phar­ma­ceu­ti­cal com­pa­nies might ex­ploit their dna to make huge profits, and even patent their genes. Na­tional Ge­o­graphic launched a sim­i­lar ven­ture called the Geno­graphic Project in 2005, but it wisely re­nounced all rights over the ge­netic ma­te­rial. It even de­vel­oped a method of sam­pling dna through a mouth­wash in­stead of blood, which many peo­ple found sus­pi­cious. Not sur­pris­ingly, half a mil­lion peo­ple signed up.

The tes­ti­mony of dna changes the con­tours of the pol­i­tics of iden­tity in cu­ri­ous and com­plex ways. In an ex­per­i­ment con­ducted by so­ci­ol­o­gist Wendy Roth at the

Univer­sity of Bri­tish Columbia, a woman who found she had a Jewish past was in­vited to a syn­a­gogue but she found the re­li­gion sti­fling. Some who dis­cov­ered they had Na­tive Amer­i­can ties felt con­fused over whether they should avail of gov­ern­ment largesse that went along with that iden­tity.

dna could also re­vise per­sonal bi­og­ra­phy in un­flat­ter­ing ways. For in­stance, when it ex­posed Thomas Jef­fer­son as hav­ing sired many kids through a black slave. Or when Hol­ly­wood ac­tor Ben Af­fleck tried to sup­press the fact that some of his an­ces­tors were slave-own­ers. Ances­try tests are not com­mon in In­dia yet, pre­sum­ably be­cause it is still ex­pen­sive (about 15,000), or per­haps they don’t want to know con­sid­er­ing how fiercely In­di­ans hold on to their iden­ti­ties of caste, com­mu­nity and re­li­gion. Imag­ine a Brah­min find­ing out he or she has roots in a Dalit caste.

Any­way, ge­neti­cists are us­ing the same tool to re­fine pre­his­tory by tap­ping into the global dna repos­i­to­ries of com­pa­nies like Na­tional Ge­o­graphic—we now know, for in­stance, that we are not pedi­greed as our an­ces­tors had sex with ar­chaic hu­man species like Ne­an­derthals in Europe, Deniso­vans in Siberia, and Hob­bits in In­done­sia, or that the Aus­tralian abo­rig­ines are re­lated to some tribes in South In­dia, sug­gest­ing the early hu­mans from Africa took the coastal route to Aus­tralia. But it is now be­ing used to throw light on messy his­to­ries of an­cient and me­dieval worlds too—for in­stance, whether the present-day Bri­tons are de­scen­dant of Ger­manic tribes.

It is the task of his­to­ri­ans, who look at writ­ten records, and arche­ol­o­gists, who work with ma­te­rial sources, to re­con­struct the past in as plau­si­ble a man­ner as pos­si­ble. The trou­ble is that the farther we go back, the sparser and flim­sier the ev­i­dence gets, which willy-nilly ren­ders any in­ter­pre­ta­tion of what may have hap­pened not only am­bigu­ous but also con­tentious as it has to reckon with fiercely-held prej­u­dices of re­li­gion, na­tion or po­lit­i­cal ide­ol­ogy.

Ge­netic his­to­ri­ans have gate-crashed into the en­ter­prise of putting to­gether the scat­tered, miss­ing, and dis­torted pieces of this im­pos­si­ble jig­saw. Noth­ing il­lus­trates this more tellingly than the long­stand­ing con­tro­versy among his­to­ri­ans over whether an­cient In­di­ans who spoke San­skrit were im­mi­grants from the steppes of Cen­tral Asia or were they na­tives.

dna as a tes­ta­ment of his­tory has com­pli­cated the de­bate. Till re­cently, stud­ies on mi­to­chon­drial dna (which is passed on from mother to daugh­ter) found lit­tle trace of for­eign genes in In­di­ans. How­ever, more re­cent stud­ies of dna on the Y chro­mo­some (y-dna, which is passed on from fa­ther to son) have found mark­ers shared by peo­ple from South Asia, Europe and Cen­tral Asia, thus favour­ing the Aryan mi­gra­tion hy­poth­e­sis.

Pre­dictably, Hindu na­tion­al­ists at­tacked the y-dna stud­ies as yet an­other ex­am­ple of Euro­cen­tric bias while some re­searchers quib­bled that the study sam­ple did not cap­ture the ge­netic di­ver­sity of In­di­ans.

Cu­ri­ously, even as ge­neti­cists spar with each other over this enigma of his­tory, his­to­ri­ans ap­pear con­spic­u­ous by their si­lence. Be­sides the ob­vi­ous rea­son that they can nei­ther un­der­stand nor scru­ti­nise it, they ac­cuse the new up­starts of cherry pick­ing his­tor­i­cal facts that fit the hy­poth­e­sis sug­gested by dna. As the Prince­ton his­to­rian Ni­cola di Cosmo asked, “if the “knowl­edge” that in­forms the def­i­ni­tion and de­scrip­tion of his­tor­i­cal pop­u­la­tions, or events such as con­quests and mi­gra­tions, or even the bare chronol­ogy, is su­per­fi­cial or wrong, can the sci­en­tific re­sults ob­tained through dna tests still be use­ful?”

That said, as ge­netic in­ter­ven­tions into his­tory grow, one hopes that his­to­ri­ans, arche­ol­o­gists, and ge­neti­cists will find ways of talk­ing and col­lab­o­rat­ing with each other if we are to take a more nu­anced, sub­tle, and less big­oted view of our past. As Prince­ton Univer­sity his­to­rian Keith Wailoo ar­gues in Ge­net­ics and the Un­set­tled Past, “what­ever the data we draw upon to an­swer the ques­tion who am I… we en­gage in a will­ful par­ing down of mul­ti­ple lines of de­scent… the col­li­sion of dna, race, and his­tory is as much about remap­ping the un­set­tled past as it is about shap­ing the un­set­tled present and imag­in­ing the fu­ture stretch­ing out be­fore us.” This monthly sec­tion will ex­plore the tan­gled web of modern ideas about science and en­vi­ron­ment across space and time

TARIQUE AZIZ / CSE

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