▁ 2 0 0 5 ▁using ▁of ▁B LA ST N , ▁MA FF T , ▁very ▁vig orous ▁gen ome ▁ma ppings , ▁and ▁ph y log en ic ▁analysis . ▁Ac ross ▁the ▁animal ▁kingdom , ▁A pis ▁m ell if era , ▁from ▁ph yl um ▁Ar th rop oda , ▁and ▁H yd ra ▁magn ip ap ill ata , ▁from ▁ph yl um ▁C n id aria , ▁are ▁respectively ▁the ▁first ▁and ▁second ▁animals ▁with ▁the ▁highest ▁ratio ▁of ▁NUM T s ▁to ▁the ▁total ▁size ▁of ▁the ▁nuclear ▁gen ome ▁while ▁Mon odel ph is ▁Dom est ica , ▁or ▁Gray ▁short - ta iled ▁op os sum , ▁is ▁the ▁record ▁holder ▁for ▁NUM T ▁frequency ▁among ▁verte br ates . ▁Similar ▁to ▁animals , ▁NUM T s ▁are ▁abund ant ▁in ▁the ▁plants ▁and ▁the ▁longest ▁NUM T ▁fragment ▁known ▁so ▁far , ▁a ▁ 6 2 0 - kb ▁partially ▁dup licated ▁insert ion ▁of ▁the ▁ 3 6 7 - kb ▁m t D NA ▁of ▁Arab id opsis ▁th al iana , ▁was ▁reported . ▁ ▁Mechan ism ▁of ▁NUM T ▁insert ion ▁NUM T ▁insert ion ▁into ▁the ▁nuclear ▁gen ome ▁and ▁its ▁pers istence ▁in ▁the ▁nuclear ▁gen ome ▁initi ated ▁by ▁physical ▁delivery ▁of ▁mit och ond rial ▁DNA ▁to ▁the ▁nucle us . ▁This ▁step ▁follows ▁by ▁the ▁m t D NA ▁integration ▁into ▁the ▁gen ome ▁through ▁a ▁non - hom olog ous ▁end ▁joining ▁mechanism