Phylogenetic analysis of different geographical strains of Ehrlichia canis based on amino acid sequences of gp36 protein. The amino acid sequences of gp36 protein of E. canis obtained in this study and available in GenBank were used to construct phylogenetic tree by the neighbor-joining method. Bootstrap values were calculated with 1000 replicates. Filled circle indicates E. canis strain XJ-2, XJ-6, XJ-21, and XJ-35 identified in this study. The GenBank accession numbers of 42 strains of E. canis were as follows: DJ (North Carolina), DQ146153.1; Florida, DQ146152.1; Cameroon 71, DQ146155.1; Sao Paulo, DQ146154.1; Louisiana, DQ146151.1; Demon, DQ085429.1; Oklahoma, DQ085428.1; Jake, DQ085427.1; Londrina, JX312080; 70C, KF233414.1; 56C, KF233413.1; 1055, KT363877.1; 533, KT363876.1; 36, KT363875.1; CM196, MF771085.1; CM180, MF771084.1; 222, KC479021.1; 171, KC479020.1; 105, KC479019.1; Muzaffargarh3, MH608290.1; Kasur2, MH608289.1; Muzaffargarh2, MH549199.1; Muzaffargarh1, MH549198.1; Rawalpindi2, MH549197.1; Rawalpindi1, MH549196.1; Kasur1, MH549195.1; 46, KT357370.1; 37y97, KT357369.1; Ranana, EU118961; 611, EF636663; Nether, KC935387.1; NGR, JN982341.1; TWN1, EF551366.1; TWN3, EF651794.1; TWN17, HQ009756.1; TWN4, EU139491.1; TWN2, EF560599.1; DB63, MG905720.1; B2-15, MG905719.1; B1-17, MG905718.1; B1-7, MG905717.1; B16, MG905716.1; B12, MG905714.1; DB51, MG905713.1; mkk2, MG905711.1; XJ-2, MN366176; XJ-6, MN366177; XJ-21, MN366178; XJ-35, MN366179.