▁in ▁turn ▁stabil izes ▁the ▁leaving ▁hydro x ide ▁ion . ▁ ▁Us es ▁in ▁research ▁ ▁H ind III ▁as ▁well ▁as ▁other ▁type ▁II ▁restriction ▁end on uc leases ▁are ▁very ▁useful ▁in ▁modern ▁science , ▁particularly ▁in ▁DNA ▁sequ encing ▁and ▁mapping . ▁ ▁Un like ▁type ▁I ▁restriction ▁en zym es , ▁type ▁II ▁restriction ▁end on uc leases ▁perform ▁very ▁specific ▁cle aving ▁of ▁DNA . ▁Type ▁I ▁restriction ▁en zym es ▁recognize ▁specific ▁sequences , ▁but ▁cle ave ▁DNA ▁randomly ▁at ▁sites ▁other ▁than ▁their ▁recognition ▁site ▁whereas ▁type ▁II ▁restriction ▁en zym es ▁cle ave ▁only ▁at ▁their ▁specific ▁recognition ▁site . ▁ ▁Since ▁their ▁discovery ▁in ▁the ▁early ▁ 1 9 7 0 s , ▁type ▁II ▁restriction ▁en zym es ▁have ▁revolution ized ▁the ▁way ▁scient ists ▁work ▁with ▁DNA , ▁particularly ▁in ▁gen etic ▁engineering ▁and ▁mole cular ▁bi ology . ▁ ▁Major ▁uses ▁of ▁type ▁II ▁restriction ▁en zym es ▁include ▁gene ▁analysis ▁and ▁cl oning . ▁ ▁They ▁have ▁proven ▁to ▁be ▁ideal ▁model ing ▁systems ▁for ▁the ▁study ▁of ▁protein - n uc le ic ▁acid ▁interactions , ▁structure - function ▁relationships , ▁and ▁the ▁mechanism ▁of ▁evolution . ▁ ▁They ▁make ▁good ▁ass ays ▁for ▁the ▁study ▁of ▁gen etic ▁mut ations ▁by ▁their ▁ability ▁to ▁specifically ▁cle ave ▁DNA ▁to ▁allow ▁the ▁removal ▁or ▁insert ion ▁of ▁DNA . ▁ ▁Through ▁the ▁use ▁of ▁restriction ▁en zym es , ▁scient ists ▁are ▁able ▁to ▁modify , ▁insert ,