Caracterização genética da raça bovina Crioulo Lageano por marcadores moleculares RAPD

Abstract

Resumo -O objetivo deste trabalho foi a caracterização genética da raça bovina Crioulo Lageano por marcadores RAPD em comparação com as raças Holandesa e Nelore. Foram selecionados 43 primers, que geraram 77 bandas polimórficas. Os animais foram distribuídos em cinco subgrupos de Crioulo Lageano (I a V), e um subgrupo em cada uma das raças Holandesa (VI) e Nelore (VII). A maior parte da variância genética total (65,05%) foi causada pela diferença de indivíduos dentro dos grupos, e o restante pelas diferenças entre grupos. A análise conjunta dos grupos I a V apresentou variabilidade genética entre grupos de 25,28% e dentro dos grupos de 74,72%. A diversidade gênica vem se mantendo ao longo das gerações no núcleo de conservação do Crioulo Lageano. A raça Holandesa apresentou a menor diversidade gênica (0,1204), e a Crioulo Lageano a maior (0,3154). A maior distância genética (0,3747) foi entre as raças Nelore e Holandesa. Os grupos de Crioulo Lageano apresentaram diferenças entre si e apenas alguns indivíduos de cada grupo posicionaram-se junto a outros grupos. A técnica RAPD é capaz de estimar a distância genética entre raças ou populações e de auxiliar na escolha de indivíduos, visando aos trabalhos de conservação de recursos genéticos.Termos para indexação: Bos taurus, Bos indicus, bovino, marcador genético, variação genética. Genetic characterization of Criollo Lageano cattle by RAPD markersAbstract -The objective of this study was to characterize genetically the Crioulo Lageano cattle breed, using RAPD markers and compare it to the Holstein and Nelore breeds. Forty three primers were selected, and they generated 77 polymorphic bands. Seven groups were studied: 5 subgroups of Crioulo Lageano (I to V) and one each Holstein (VI) and Nellore (VII). Using all groups, the greater part of the genetic variance (65.05%) was due to differences within groups and the rest due to differences between groups. Using five Crioulo Lageano groups (I to V) the results showed 25.28% variation between groups and 74.72% within groups. Genetic diversity has been maintained throughout the generations in this conservation nucleus. The Holstein breed presented the lowest genetic diversity (0.1204) while the Crioulo Lageano herd presented the highest (0.3154). The observed genetic differences were highest between Nellore and Holstein breeds (0.3747), as expected. In general, the Crioulo Lageano groups formed distinct groups and only a few animals from one group were positioned within another group. The RAPD marker technique is adequate to estimate genetic distances between breeds and populations, as well as for use in the choice of individuals for breeding within populations, for conservation of genetic resources.

Reproductive characteristics of Crioulo Lageano breed bulls (Bos taurus) at puberty

“…In Nellore bulls the DPP was 18.1 ± 1.9 months of age and also did not influence the onset of other reproductive events in these bulls (Freneau et al, 2006). Based on facts above discussed and that the Crioulo Lageano breed was only submitted to the pressure of natural selection for over three centuries (Spritze et al, 2003), it is suggested that the interval of six months between the onset of puberty in the most and least precocious bull, observed in this experiment, indicates the possibility of selecting those bulls which are potentially more precocious and fertile.…”

“…Since this period, the potential of maximum heterosis in the F1 generation has become well known and the results were attributed only to the imported breeds. Due the widespread increase in cross-breeding between these breeds, the population of the Crioulo Lageano breed has been decreasing drastically and a strong tendency persists toward replacement of local breeds with exotic breeds, mainly in southern Brazil (Spritze et al, 2003).…”

Cluster evaluation of Brazilian and Moroccan goat populations using physical measurements

“…It is observed that the intragroup average distance is always lower than intergroup average distance. Higher variability between individuals within populations than among populations was also found by Spritze et al (2003) and by Serrano et al (2004) in Brazilian cattle; by Paiva et al (2005) The intragroup distance D (Table 5) ranged from 0.43 (group II) to 1.02 (group III). The presence of Nambi ecotype in group III explains its greater intragroup heterogeneity.…”

Genetic diversity of captive spotted paca (Agouti paca) from south east Brazil assessed by the RAPD-PCR technique

“…AMOVA (analysis of molecular variance) was to analyze the genetic structure, using the Arlequim v. 2 program that uses an AMOVA adaptation for dominants data, such as RAPD (Stewart Jr & Excoffier, 1996;Schneider at al., 2000). The TFPGA v. 1.3 -Tools for population genetic analysis (Miller, 1997) was used for further among and within population analyses.…”