Associação de polimorfismos no gene da u-calpaína com a maciez da carne em animais da raça Nelore.

Os bovinos de origem Bos indicus são preferidos nos trópicos devido a sua maior resistência as adversidades ambientais. No entanto, estes animais não produzem carne tão macia quanto os taurinos. A seleção assistida por marcadores relacionados à maciez da carne, como é o caso da protease calpaína, pode auxiliar na melhoria da característica. Nesse trabalho, foram utilizados 229 animais da raça Nelore. Após a extração do DNA de amostras de sangue, por desproteinização em presença de NaCl a identificação e determinação dos polimorfismos para três marcadores (CAPN316, CAPN530 e CAPN4751) foi realizada pelo sistema de detecção TaqManTM utilizando-se PCR em Tempo Real. A análise de maciez da carne, aos 7, 14 e 21 dias de maturação, foi realizada com amostras de carne do Longissimus dorsi, retiradas entre a 12a e 13ª costela e cisalhadas utilizando-se um Warner Braztler Shear Force. Os polimorfismos dos marcadores CAPN316 e CAPN530 não apresentaram efeitos significativos (P>0,05) para a maciez da carne aos 7, 14 e 21 dias de maturação. Foram verificados efeitos significativos para os polimorfismos do CAPN4751 em relação à maciez da carne aos 7 (P=0.001), 14 (P=0.005) e 21 (P=0.006) dias de maturação

Efeito médio de substituição alélica para os polimorfismos CAPN4753 e UOGCAST no gene da calpaína e calpastatina.

Os objetivos deste trabalho foram avaliar possíveis interações alélicas para os polimorfismos nos genes da µ-calpaína (CAPN4753) e da calpastatina (UOGCAST1), ligados a característica de maciez da carne. Nesse trabalho, foram utilizados 590 animais da raça Nelore. Após a extração do DNA de amostras de sangue por precipitação em NaCl. A identificação e determinação dos polimorfismos para os marcadores foram realizadas pelo sistema de detecção TaqManTM utilizando-se PCR em Tempo Real. A análise de maciez da carne, aos 7, 14 e 21 dias de maturação, foi realizada com amostras de carne do Longissimus dorsi, retiradas entre a 12ª e 13ª costela e cisalhadas utilizando-se um Warner Bratzler Shear Force. Foram observados resultados significativos para o efeito médio de substituição aos 14 dias de maturação da carne, apenas para o polimorfismo no gene da calpastatina, e aos 21 dias para ambos os polimorfismos (CAPN4753 e UOGCAST1)

Genotypic and allelic frequencies of gene polymorphisms associated with meat tenderness in Nellore beef cattle.

The objectives of this study were to characterize the allelic and genotypic frequencies of polymorphisms in the μ-calpain and calpastatin genes, and to assess their association with meat tenderness and animal growth in Nellore cattle. We evaluated 605 Nellore animals at 24 months of age, on average, at slaughter. The polymorphisms were determined for the molecular markers CAPN316, CAPN530, CAPN4751, CAPN4753, and UOGACAST1. Analyses of meat tenderness at 7, 14, and 21 days of maturation were performed in samples of longissimus thoracis obtained between the 12th and 13th rib and sheared using a Warner Bratzler Shear Force. Significant effects were observed for meat tenderness at days 7, 14, and 21 of maturation for the marker CAPN4751, at day 21 for the marker CAPN4753, and at days 14 and 21 for the marker UOGCAST1. For genotypic combinations of markers, the results were significant for the combination CAPN4751/UOGCAST1 in the three maturation periods and CAPN4753/UOGCAST1 at days 14 and 21 of maturation

Association of single nucleotide polymorphisms in the bovine leptin and leptin receptor genes with growth and ultrasound carcass traits in Nellore cattle

Given the important role of leptin in metabolism, we looked for a possible association of leptin and leptin receptor polymorphisms with carcass and growth traits in Nellore cattle. We examined associations of leptin and leptin receptor SNPs with ultrasound carcass (longissimus dorsi muscle area (ribeye area), backfat thickness and rump fat thickness and growth traits (weaning weight adjusted to 210 days of age, yearling weight adjusted to 550 days of age, weight gain of weaning to yearling and scrotal circumference adjusted to 550 days of age) of 2162 Bos primigenius indicus (Nellore) animals. Allele and genotypic frequencies were calculated for each marker. Allele substitution, additive and dominance effects of the polymorphisms were also evaluated. Some alleles of the molecular markers had low frequencies, lower than 1%, in the sample analyzed, although the same polymorphisms described for B. p. taurus cattle were found. Due to very low allelic frequencies, the E2JW, A59V and UASMS2 markers were not included in the analysis, because they were almost fixed. E2FB was found to be significantly associated with weight gain, ribeye area and backfat thickness. The promoter region markers, C963T and UASMS1, were also found to be significantly associated with ribeye area. T945M was significantly associated with weight gain. We conclude that the leptin and receptor gene markers would be useful for marker-assisted selection.FUNPEC/RPFUNPEC/R

A phylogenetic classification of the world’s tropical forests

Knowledge about the biogeographic affinities of the world’s tropical forests helps to better understand regional differences in forest structure, diversity, composition and dynamics. Such understanding will enable anticipation of region specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present the first classification of the world’s tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (1) Indo-Pacific, (2) Subtropical, (3) African, (4) American, and (5) Dry forests. Our results do not support the traditional Neo- versus Palaeo-tropical forest division, but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar and India. Additionally, a northern hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern hemisphere forests