ing ▁them ▁in ▁order ▁for ▁polym er ases ▁and ▁lig ases ▁to ▁be ▁able ▁to ▁complete ▁NUM T ▁insert ion ▁( figure ▁ 3 ). ▁ ▁Post - insert ion ▁modification : The ▁complex ▁pattern ▁of ▁NUM T ▁in ▁comparison ▁with ▁the ▁single ▁mit och ond rial ▁piece , ▁the ▁appearance ▁of ▁non - continu ous ▁mit och ond rial ▁DNA ▁in ▁the ▁nuclear ▁gen ome , ▁and ▁possibly , ▁different ▁orientation ▁of ▁these ▁fragments ▁are ▁the ▁evidence ▁of ▁post - insert ion ▁processes ▁of ▁NUM T ▁within ▁the ▁nuclear ▁gen ome . ▁The ▁caus ation ▁of ▁these ▁complex ▁patterns ▁might ▁be ▁the ▁result ▁of ▁multiple ▁NUM T ▁insert ions ▁at ▁insert ional ▁hot sp ots . ▁In ▁addition , ▁dup lication ▁after ▁insert ion ▁cont ributes ▁to ▁NUM T ▁divers ity . ▁NUM T s ▁have ▁no ▁self - rep lic ating ▁mechanism ▁or ▁trans position ▁mechanism ; ▁therefore , ▁NUM T ▁dup lication ▁is ▁expected ▁to ▁occur ▁in ▁tan dem ▁or ▁to ▁involve ▁larger ▁segment al ▁dup lication ▁at ▁rates ▁representative ▁of ▁the ▁rest ▁of ▁the ▁gen ome . ▁ ▁Ev idence ▁for ▁NUM T ▁dup lications ▁that ▁are ▁not ▁in ▁proxim ity ▁to ▁other ▁NUM T s ▁is ▁present ▁in ▁many ▁genom es ▁and ▁probably ▁happens ▁as ▁part ▁of ▁segment al ▁dup lication . ▁However , ▁dup lications ▁of ▁recent ▁human - specific ▁NUM T s ▁as ▁part ▁of ▁segment al ▁dup lication ▁seem ▁to ▁be ▁rare ; ▁in ▁humans , ▁only ▁a ▁few ▁NUM T s ▁are ▁found ▁to