▁Monte ▁Rom ano ▁in ▁the ▁province ▁of ▁V iter bo ; ▁a ▁her d ▁of ▁approximately ▁ 2 0 0 ▁is ▁at ▁Pon z ano ▁Rom ano ▁in ▁the ▁province ▁of ▁Rome , ▁and ▁others ▁are ▁in ▁the ▁province ▁of ▁R iet i . ▁ ▁History ▁ ▁The ▁bre ed ▁register ▁for ▁the ▁Caval lo ▁Rom ano ▁della ▁Mare m ma ▁Laz iale ▁was ▁opened ▁on ▁ 1 9 ▁October ▁ 2 0 1 0 , ▁and ▁the ▁bre ed ▁standard ▁confirmed ▁by ▁Minister ial ▁Dec ree ▁ 2 7 2 0 2 , ▁dated ▁ 1 ▁December ▁ 2 0 1 0 . ▁DNA ▁testing ▁had ▁shown ▁that ▁the ▁traditional ▁working ▁horse ▁of ▁the ▁Mare m ma ▁of ▁Laz io ▁was ▁not ▁only ▁phys ically ▁but ▁gen et ically ▁distinguish able ▁from ▁its ▁counter part ▁in ▁the ▁T us can ▁Mare m ma , ▁the ▁Mare m man o , ▁with ▁which ▁it ▁had ▁previously ▁been ▁class ed . ▁The ▁two ▁populations ▁are ▁reported ▁as ▁having ▁common ▁orig ins ▁but ▁limited ▁overlap , ▁with ▁the ▁Roman ▁horse ▁showing ▁greater ▁vari ability ▁and ▁a ▁higher ▁proportion ▁of ▁" anc est ral " ▁gen es ; ▁Ri pert ▁reports ▁inform ally ▁that ▁the ▁Caval lo ▁Rom ano ▁della ▁Mare m ma ▁Laz iale ▁has ▁ 3 8 . 5 % ▁gen es ▁of ▁the ▁original ▁type , ▁while ▁the ▁registered ▁Mare m man o ▁population ▁has ▁only ▁ 1 2 %. ▁ ▁The ▁gen etic ▁study , ▁carried ▁out ▁by ▁the ▁Cons or z