Is the American Zebu really Bos indicus?

Abstract

The American continent was colonized in the 16th century by Europeans who first introduced cattle of Bos taurus origin. Accounts register introduction of Bos indicus cattle into South America in the 19th and continuing through the 20th century, and most reported imports were males derived from the Indian subcontinent. In the present study we show, by using mitochondrial DNA (mtDNA) polymorphism, major participation of matrilineages of taurus origin in the American Zebu purebred origin, i.e., 79, 73 and 100% for the Nellore, Gyr and Brahman breeds, respectively. Moreover, we have created a restriction map identifying polymorphism among B. taurus and B. indicus mtDNA using three restriction enzymes. Results are discussed concerning American Zebu origins and potential use of this information for investigating the contribution of cytoplasmic genes in cattle production traits.<br>O continente americano foi colonizado no século XVI por europeus que fizeram as primeiras introduções de bovinos, de origem taurina. Os registros das primeiras importações de Zebus para a América do Sul datam do século XIX e continuam até o século XX, constituídos na maioria por machos do sub-continente indiano. Neste artigo, demonstramos, através dos estudos de polimorfismos no DNA mitocondrial (mtDNA), uma participação majoritária de matriarcas de origem taurina na formação do Zebu PO americano (79% dos animais analisados da raça Nelore, 73% na Gir e 100% na Brahman). Ainda, criamos um mapa de restrição com os polimorfismos descritos de três enzimas de restrição. Os resultados estão discutidos em termos da origem do Zebu americano e da aplicação deste conhecimento no estudo dos efeitos do genoma citoplasmático, nas características produtivas dos bovinos

African and European mitochondrial haplotypes in South American Creole cattle

“…One of the haplotypes was identical to one Creole haplotype (CC1), while the other was unique (BRA). This finding was not completely unexpected, since taurine mtDNA was also identified in 23 Brahman animals examined by RFLP (Meirelles et al, 1999). Zebu cattle were brought from India to North America at the beginning of the 19th century.…”

Cytogenetic and molecular analysis of the Pantaneiro cattle breed

“…Bos taurus indicus animals used in absorbing crosses in the late 19 th century were exclusively males. Meirelles et al (1999), using the mtDNA polymorphism, showed evidence of the participation of females of taurine origin, in the formation of the pure American Zebu breeds. According to these authors, of the Brazilian zebuines analyzed (Nelore and Gyr), 58% had mtDNA of taurine origin, indicating a strong influence of taurine breeds in the formation of the South American Zebu.…”

“…After DNA quantification, ~100 ng DNA of each sample was used for amplification by PCR (polymerase chain reaction), using a termocycler (Genius, Techne Cambridge Limited, England), and primers sequence according to Meirelles et al (1999). The PCR reaction mixture consisted of 10 pmol of each of the forward (5'-GCCCGAAACCAGACGAGCTAC-3') and reward (5'-TTGTATGAATGGCCGCACGAGG-3') primers; 20 mM Tris-HCl (pH 8,4); 50 mM KCl; 3.5 mM MgCl 2 ; 600 mM of each dGTP, dATP, dTTP and dCTP (dNTP; Gibco BRL, Life Technologies, USA), and 1.25 U Taq polymerase (Invitrogen, USA), in a final volume of 30 µL.…”

“…This fragment encompasses the region between nucleotides 1692 and 2441 of mtDNA. The amplification product was digested overnight, at 37ºC, with 5IU of HpaI, wich has one restriction site in the B. taurus mtDNA (producing two fragments), and two amplification sites in the B. indicus mtDNA (producing three fragments) (Meirelles et al, 1999). After digestion of the amplified mtDNA, electrophoresis was carried out in 1.2% agarose gel, stained with ethidium bromide, and digestion products were visualized under ultraviolet light, in order to identify the mtDNA haplotype.…”

Efeito da proporção de DNA de origem Bos taurus em características ligadas a precocidade sexual e de acabamento na raça Nelore

“…Estudos evolutivos, principalmente relacionados ao esclarecimento da origem dos bovinos domésticos têm sido apoiados na análise do DNA mitocondrial (LOFTUS et al, 1994a e b;BRADLEY et al, 1996;MEIRELLES et al, 1999).…”