▁of ▁the ▁National ▁Academ ies ▁is ▁that ▁the ▁historic ▁population ▁of ▁Mexican ▁w olf ▁represents ▁a ▁distinct ▁evolution ary ▁line age ▁of ▁gray ▁w olf , ▁and ▁that ▁modern ▁Mexican ▁wol ves ▁are ▁their ▁direct ▁descend ants . ▁It ▁is ▁a ▁valid ▁tax onom ic ▁sub species ▁class ified ▁as ▁Can is ▁l up us ▁ba iley i . ▁ ▁Line age ▁Gray ▁wol ves ▁( Can is ▁l up us ) ▁migr ated ▁from ▁E uras ia ▁into ▁North ▁America ▁ 7 0 , 0 0 0 – 2 3 , 0 0 0 ▁years ▁ago ▁and ▁gave ▁rise ▁to ▁at ▁least ▁two ▁morph olog ically ▁and ▁gen et ically ▁distinct ▁groups . ▁One ▁group ▁is ▁represented ▁by ▁the ▁ext inct ▁Ber ing ian ▁w olf ▁and ▁the ▁other ▁by ▁the ▁modern ▁populations . ▁One ▁author ▁propos es ▁that ▁the ▁Mexican ▁w olf ' s ▁ancest ors ▁were ▁likely ▁the ▁first ▁gray ▁wol ves ▁to ▁cross ▁the ▁Ber ing ▁Land ▁Bridge ▁into ▁North ▁America ▁during ▁the ▁Late ▁Ple ist oc ene ▁after ▁the ▁ext inction ▁of ▁the ▁Ber ing ian ▁w olf , ▁colon izing ▁most ▁of ▁the ▁continent ▁until ▁pushed ▁south wards ▁by ▁the ▁newly ▁arrived ▁ancest ors ▁of ▁C . ▁l . ▁n ub ilus . ▁ ▁A ▁ha plot ype ▁is ▁a ▁group ▁of ▁gen es ▁found ▁in ▁an ▁organ ism ▁that ▁are ▁inherited ▁together ▁from ▁one ▁of ▁their ▁parents . ▁M ito ch ond rial ▁DNA ▁( m D NA ) ▁passes ▁along ▁the ▁mat ernal ▁line ▁and