José Ribamar Felipe Marques

Climatology of the Amazon region

During the many colonization cycles in the Amazon, serious difficulties hampered the development of intensive agricultural activity which would lead to expansion and the economic independence of its populations. Many investigators have tried to explain the reasons for such difficulties and frequently associate environmental factors with agricultural production problems.

Genetic characterization of Latin-American Creole cattle using microsatellite markers

Genetic diversity in and relationships among 26 Creole cattle breeds from 10 American countries were assessed using 19 microsatellites. Heterozygosities, F-statistics estimates, genetic distances, multivariate analyses and assignment tests were performed. The levels of within-breed diversity detected in Creole cattle were considerable and higher than those previously reported for European breeds, but similar to those found in other Latin American breeds. Differences among breeds accounted for 8.4% of the total genetic variability. Most breeds clustered separately when the number of pre-defined populations was 21 (the most probable K value), with the exception of some closely related breeds that shared the same cluster and others that were admixed. Despite the high genetic diversity detected, significant inbreeding was also observed within some breeds, and heterozygote excess was detected in others. These results indicate that Creoles represent important reservoirs of cattle genetic diversity and that appropriate conservation measures should be implemented for these native breeds in order to minimize inbreeding and uncontrolled crossbreeding.

Genetic Footprints of Iberian Cattle in America 500 Years after the Arrival of Columbus

Background American Creole cattle presumably descend from animals imported from the Iberian Peninsula during the period of colonization and settlement, through different migration routes, and may have also suffered the influence of cattle directly imported from Africa. The introduction of European cattle, which began in the 18th century, and later of Zebu from India, has threatened the survival of Creole populations, some of which have nearly disappeared or were admixed with exotic breeds. Assessment of the genetic status of Creole cattle is essential for the establishment of conservation programs of these historical resources. Methodology/Principal Findings We sampled 27 Creole populations, 39 Iberian, 9 European and 6 Zebu breeds. We used microsatellite markers to assess the origins of Creole cattle, and to investigate the influence of different breeds on their genetic make-up. The major ancestral contributions are from breeds of southern Spain and Portugal, in agreement with the historical ports of departure of ships sailing towards the Western Hemisphere. This Iberian contribution to Creoles may also include some African influence, given the influential role that African cattle have had in the development of Iberian breeds, but the possibility of a direct influence on Creoles of African cattle imported to America can not be discarded. In addition to the Iberian influence, the admixture with other European breeds was minor. The Creoles from tropical areas, especially those from the Caribbean, show clear signs of admixture with Zebu. Conclusions/Significance Nearly five centuries since cattle were first brought to the Americas, Creoles still show a strong and predominant signature of their Iberian ancestors. Creole breeds differ widely from each other, both in genetic structure and influences from other breeds. Efforts are needed to avoid their extinction or further genetic erosion, which would compromise centuries of selective adaptation to a wide range of environmental conditions.

Parâmetros genéticos das características produtivas e reprodutivas de búfalos na Amazônia brasileira

O objetivo deste trabalho foi estimar componentes de variância e parâmetros geneticos, incluindo correlacoes geneticas, fenotipicas e herdabilidade das caracteristicas produtivas e reprodutivas de bufalos na Amazonia brasileira. As estimativas de herdabilidade (h2) das caracteristicas variaram de 0,04 a 0,05 no primeiro intervalo entre partos, de 0,0 a 0,26 no intervalo entre partos, e de 0,0 a 0,25 no periodo de servico, refletindo grande influencia ambiental. Na idade ao primeiro parto, a herdabilidade variou de 0,12 a 0,38. Em relacao ao peso ao nascer, a raca Murrah foi a que apresentou a mais alta h2 (0,62). As correlacoes geneticas variaram de 1,00 a -1,00. Foram negativas as correlacoes geneticas entre idade ao primeiro parto e peso da femea adulta (-0,12 a -1,00 dependendo da raca), assim como as correlacoes entre periodo de servico, peso ao nascer e peso da femea adulta (0,01 a -1,00). O efeito de ambiente permanente (c2) variou de 0,000 a 0,155. Somente no intervalo entre partos para a raca Jafarabadi pode-se considerar que houve c2 significativo (0,458). O efeito materno (m2) no peso ao nascer variou de baixo a medio, nas racas Carabao, Jafarabadi, Mediterrâneo e Murrah (0,11, 0,17, 0,37, 0,04, respectivamente).

Variabilidade genética de búfalos em rebanho-núcleo com base na análise de pedigree

Parâmetros baseados na probabilidade de origem do gene foram usados para descrever a variabilidade em uma populacao de bufalos da Embrapa Amazonia Oriental. A magnitude dos resultados foi de media a baixa (por volta de 20 animais), sugerindo que poucos fundadores contribuiriam para a formacao da populacao. Dentre os 20 ancestrais que mais aportam genes aos machos - representando ao todo 71% dos alelos -, 39%, 26% e 5%, respectivamente, sao as contribuicoes marginais das racas Murrah e Mediterrâneo e seus mesticos. Para as femeas, em que os 20 ancestrais aportam 67,5% dos genes, 42% e 26%, respectivamente, sao as contribuicoes marginais das racas Murrah e Mediterrâneo.

Estimação de parâmetros genéticos para características produtivas em búfalos na Amazônia Oriental

Dados de 1.182 registros de producao de femeas bubalinas da raca Murrah e seus mesticos, parindo no periodo de 1967 a 2005, foram utilizados para estimacao de parâmetros geneticos utilizando-se o metodo de maxima verossimilhanca restrita. O modelo animal utilizado para estimacao de componentes de variância incluiu os efeitos fixos de rebanho, ano e epoca de parto, ordem de parto e duracao da lactacao e os efeitos aleatorios do animal, e ambiente permanente e temporario. As estimativas de herdabilidade foram 0,25, 0,18, 0,08 e 0,09, para producao de leite, producao de gordura, duracao da lactacao e producao de leite por dia de intervalo de parto, respectivamente. As estimativas de repetibilidade foram 0,33, 0,29 e 0,10 para producao de leite, producao de gordura e duracao da lactacao, respectivamente. As correlacoes geneticas entre producoes de leite e gordura, producao de leite com duracao da lactacao, producao de leite com producao de leite por dia de intervalo de partos, producao da gordura com duracao da lactacao, producao de gordura com producao de leite por dia de intervalo de partos e duracao da lactacao com producao de leite por dia de intervalo de partos foram 0,93; 0,76; 0,99; 0,89; 0,87 e -0,27, respectivamente. Os resultados demonstram que ganhos geneticos podem ser obtidos pela selecao das producoes de leite e gordura.

Genetic Relationships Among Five Zebu Breeds Naturalized in America Accessed with Molecular Markers

This study aims to analyze the within-breed genetic diversity and determine the genetic relationships among the most important zebu populations introduced in the American continent from Asia. Gyr (GYR), Red Sindhi (SIN), Nellore (NEL), Guzerat (GUZ) and the synthetic Brahman (BRH) breeds have been established especially in American tropical regions. Estimates of genetic structure and diversity were carried out within and among the five populations studied. The results of withinbreed genetic diversity showed medium to high medium values of diversity in all genetic parameters [observed heterozygosity (Ho)=0.622±0.022; expected heterozygosity (He)=0.662±0.023; number of alleles (Na)=5.71±1.63; and allelic richness (Ar)=4.097±0.958]. The lowest value of Ho was observed in NEL (0.569±0.019) and the highest in BRH (0.688±0.015). Lowest value of He was also observed in NEL (0.612±0.024) and the highest in BRH (0.700±0.020). Gyr, GUZ and NEL showed high estimations of inbreeding, 9.98, 7.92 and 6.83% respectively. Values of Na varied between 4.93±1.52 in GUZ and 7.04±1.99 in BRH and the Ar values ranged between 3.687±0.895 in NEL and 4.42±1.91 in SIN. On the other hand, although phenotypically, the five breeds are clearly distinguishable, the genetic analysis of structure and kinship demonstrates a total independence among GYR, GUZ and NEL, while BRH and Red Sindhi show a closed relationship. These facts support that GYR, GUZ and NEL have had a diverse origin but also different models of introgression in America. Brahman and SIN could be explained by the intervention of the Sindhi ancestors in the formation of the American synthetic Brahma.

Karyotypic evolution of ribosomal sites in buffalo subspecies and their crossbreed

Domestic buffaloes are divided into two group based on cytogenetic characteristics and habitats: the “river buffaloes” with 2n = 50 and the “swamp buffaloes”, 2n = 48. Nevertheless, their hybrids are viable, fertile and identified by a 2n = 49. In order to have a better characterization of these different cytotypes of buffaloes, and considering that NOR-bearing chromosomes are involved in the rearrangements responsible for the karyotypic differences, we applied silver staining (Ag-NOR) and performed fluorescent in situ hybridization (FISH) experiments using 18S rDNA as probe. Metaphases were obtained through blood lymphocyte culture of 21 individuals, including river, swamp and hybrid cytotypes. Ag-NOR staining revealed active NORs on six chromosome pairs (3p, 4p, 6, 21, 23, 24) in the river buffaloes, whereas the swamp buffaloes presented only five NOR-bearing pairs (4p, 6, 20, 22, 23). The F1 cross-breed had 11 chromosomes with active NORs, indicating expression of both parental chromosomes. FISH analysis confirmed the numerical divergence identified with Ag-NOR. This result is explained by the loss of the NOR located on chromosome 4p in the river buffalo, which is involved in the tandem fusion with chromosome 9 in this subspecies. A comparison with the ancestral cattle karyotype suggests that the NOR found on the 3p of the river buffalo may have originated from a duplication of ribosomal genes, resulting in the formation of new NOR sites in this subspecies.

Índices de eficiência reprodutiva de búfalos da Amazônia Oriental do Brasil

We evaluated records of reproductive management Jaffarabadi buffalo breeds, Murrah, Mediterranean, Carabao and Baio types, and their crosses, in the period from 1983 to 2005. We studied the following reproductive characteristics: Age at first calving (mean 1052.52±120.45 days), calving interval (399.69±23.78 mean days), Reproductive Efficiency (average 91.09±1, 89%), Real Adapted Fertility (average 29.30±4.40kg calf calved each year), the First Labor Productivity Adapted (mean 33.75±6.89kg) and Accumulated Productivity Adapted (mean 22.86±6.55kg calf calved each year). Influences were observed in the year of delivery and degree of blood on the female traits, suggesting that such effects should be included in genetic evaluation and selection of animals. The production indices used were of great value for the selection, and should be well studied for their interactions with the overall performance of the herd.

Genetic diversity of brazilian buffaloes (Bubalus bubalis) using DNA microsatellites

EnglishFoi estudada a diversidade genetica de bufa- los do Brasil utilizando-se vinte e cinco marcado- res microssatelites (CSSM41, CSSM8, CSRM60, CSSM33, BM1818, HEL13, MAF65, CSSME70, HSC, BRN, CSSM36, CSSM22, HAUT24, BM1824, SRCRSP8, TGLA227, ILSTS33, INRA23, BM8125, CSSM19, INRA37, CSSM66, ILSTS011, OarFCB48, SPS115). Foram analisadas amostras colhidas ao acaso de cinco populacoes, ou seja, racas Cara- bao, Jafarabadi, Mediterrâneo e Murrah, mais o tipo Baio. Em geral, os valores para a diferenca entre as heterozigosidades (H o - H e ) foram bastan- tes pequenas, significando equilibrio nos marca- dores utilizados para este tipo de estudo. Os valores do GST demonstraram um nivel alto de diferenciacao genetica e os da estatistica F: Fis (f), Fst (q) e Fit (F) demonstraram que os marca- dores utilizados permitem inferir informacoes adequadas sobre as populacoes, podendo-se deduzir que os grupos Baio, Carabao, Jafarabadi e Mediterrâneo apresentam-se mais homogeneos que o grupo Murrah, o qual mostra niveis altos de endogamia. Os resultados dos estudos de distância genetica mostraram que as populacoes de Baio, Mediterraneo e Murrah, agrupando-se em um clus- ter comum, demonstra alta similaridade genetica, nao obstante as suas divergencias fenotipicas, confirmando que o grupo Carabao constitui uma diferente subespecie. Os resultados, principal- mente das populacoes de Baio e Carabao, mostram o exito do trabalho de con-servacao genetica e a necessidade de se desenvolver novas estrategias para a conservacao do germoplasma dos bufalos do Brasil. EnglishGenetic diversity of Brazilian buffaloes is studied using a panel of twenty-five DNA microsatellite markers (CSSM41, CSSM8, CSRM60, CSSM33, BM1818, HEL13, MAF65, CSSME70, HSC, BRN, CSSM36, CSSM22, HAUT24, BM1824, SRCRSP8, TGLA227, ILSTS33, INRA23, BM8125, CSSM19, INRA37, CSSM66, ILSTS011, OarFCB48, SPS115). Forty samples randomly chosen from each of the Brazilian Buffaloes populations (Carabao, Jafarabadi, Mediterraneo, Murrah and Baio) were analyzed. Anyway the homogeneity test between observed and expected heterozygosity and the results of the Hardy- Weinberg equilibrium pointed out the stability of Baio and Carabao populations. Genetic distances, factorial analysis and individual assignation values showed that Baio, Mediterraneo and Murrah form a common genetic cluster as shown by their high genetic similarity in spite of their morphological divergence. That Carabao is a member of a different subspecies is confirmed. These findings demonstrate the success of Brazilian Baio and Carabao conservation efforts, and point to the need to develop new strategies of conservation for the remaining Brazilian buffalo populations.