Related by context. Frequent words. (Click for all words.) 35 Bronze Age 35 ancient 35 occurs naturally 33 originated 32 underlie 31 Middle Ages 31 colonized 30 coexisted 30 transmissible 30 inhabited 30 seventeenth century 29 origins 29 behave differently 29 ancestor 29 susceptible 28 precursors 28 inhabit 28 existed 28 origin 28 #th century 27 deeply rooted 27 evolved 27 originate 27 sixteenth century 27 ancient Greeks 26 predate 26 Discovered 26 colonize 26 pose threat 25 uncommon 25 resemble 25 underlies 25 undetected 25 discovered 25 migrating 25 extant 25 predominant 25 predating 25 closely resemble 25 exist 25 diverged 25 coexist 24 traces 24 detected 24 infect humans 24 eighteenth century 24 excrete 24 rooted 24 predated 24 adapted 24 migrated 24 migrate 23 prevalent 23 endemic 23 steeped 23 nineteenth century 23 correlate 23 uncovered 23 survive 23 closely resembled 23 traced 22 predates 22 originating 22 analogous 22 predominate 22 contain 22 direct descendant 22 exists 21 belong 21 commonly 21 evolve 21 resembles 21 resembled 21 pervade 21 processed 21 detect 21 seep 20 lived 20 possess 20 contaminate 20 pose 20 predominates 20 vary greatly 20 predominated 20 originates 20 studied 20 largely unaffected 19 indistinguishable 19 linked 19 clustered 19 flourished 19 distinguishable 19 typify 19 migrates 19 vary widely 19 permeated 19 infect 19 thrive 19 spillovers 19 persist 19 Indian subcontinent