Phylogeography of New World isolates of Anaplasma marginale based on major surface protein sequences $ Jose ´ de la Fuente a,* , Ronald A. Van Den Bussche b , Jose C. Garcia-Garcia a , Sergio D. Rodrı ´guez c , Miguel A. Garcı ´a c , Alberto A. Guglielmone d , Atilio J. Mangold d , Lygia M. Friche Passos e , Mucio F. Barbosa Ribeiro f , Edmour F. Blouin a , Katherine M. Kocan a a Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, 250 McElroy Hall, Stillwater, OK 74078, USA b Department of Zoology and Collection of Vertebrates, Oklahoma State University, Stillwater, OK 74708, USA c CENID—Parasitologı ´a Veterinaria, Instituto Nacional de Investigaciones Forestales, Agrı ´colas y Pecuarias, SAGARPA. Apdo. Postal 206, CIVAC 62550 Jiutepec, Morelos, Mexico d Instituto Nacional de Tecnologı ´a Agropecuaria, Estacio ´n Experimental Agropecuaria Rafaela, Santa Fe, Argentina e Escola de Veterinaria, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil f Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil Received 11 December 2001; received in revised form 25 April 2002; accepted 20 May 2002 Abstract Gene and protein sequences of major surface proteins (MSP) 1a and 4 of Anaplasma marginale (Rickettsiales: Anaplasmataceae) were used to infer phylogenetic relationships between New World isolates from Argentina, Brazil, Mexico and the United States. Seventeen isolates of A. marginale plus two outgroup taxa (A. centrale and A. ovis) were used for maximum-parsimony analysis of MSP4, while 20 isolates were used for phylogenetic analysis of MSP1a. msp4 analysis provided strong bootstrap support for a Latin American clade and, within this clade, support was detected for Mexican and South American clades. Isolates of A. marginale from the United States also grouped Veterinary Microbiology 88 (2002) 275–285 $ The GenBank accession numbers for msp1a sequences of Texas, Brazil, Salta and Virasoro A. marginale isolates are AF428091–AF428094 and for msp4 sequences of Illinois, Texas, Mexico, Morelos, Veracruz, Yucatan, Brazil, Salta and Virasoro A. marginale isolates and the Israel isolate of A. centrale are AF428081– AF428090. * Corresponding author. Tel.: þ1-405-744-0372; fax: þ1-405-744-5275. E-mail address: jose_delafuente@yahoo.com (J. de la Fuente). 0378-1135/02/$ – see front matter # 2002 Elsevier Science B.V. All rights reserved. PII:S0378-1135(02)00122-0