S. R. Paiva

Genetic variability of Pantaneiro horse using RAPD-PCR markers

Blood samples were collected from Pantaneiro Horses in five regions of Mato Grosso do Sul and Mato Grosso States. Arabian, Mangalarga Marchador and Thoroughbred were also included to estimate genetic distances and the existing variability among and within these breeds by RAPD-PCR (Random Amplified Polymorphic DNA - Polymerase Chain Reaction) molecular markers. From 146 primers, 13 were chosen for amplification and 44 polymorphic bands were generated. The analysis of molecular variance (AMOVA) indicated that the greatest portion of detected variability was due to differences between individuals within populations (75.47%). Analysis of the genetic variability between pairs of populations presented higher estimates for the five Pantaneiro populations with the Arabian breed, while lowest estimates were presented by pairs formed among the Pantaneiro populations with the Mangalarga Marchador. Highest genic diversity was shown by the Pantaneiro (0.3396), which also showed highest genetic distance with the Arabian and lowest with Mangalarga Marchador breed. UPGMA dendrogram showed distinct differences between naturalized (Pantaneiro and Mangalarga Marchador) and exotic (Arabian and Thoroughbred) breeds. In the dendrogram generated by UPGMA method, the similarity matrix generated by the Jaccard coefficient showed distinction between the naturalised breeds, Pantaneiro and Mangalarga Marchador, and the exotic breeds, Arab and English Thoroughbred. Results suggest that the Pantaneiro presents a higher genetic variability than the other studied breeds and has a close relationship with the Mangalarga Marchador.

Crescimento e mortalidade em um rebanho de conservação de caprinos Marota no Brasil.

O caprino Marota consiste em um importante recurso genetico adaptado ao Semiarido brasileiro e encontra-se em risco de extincao. A Embrapa Meio-Norte mantem um nucleo de conservacao destes caprinos no municipio de Castelo do Piaui, regiao de transicao caatinga-cerrado. O manejo deste rebanho e semi-extensivo para sobrepujar as caracteristicas de rusticidade do ecotipo Marota. Esta pesquisa foi realizada com o objetivo de monitorar o desempenho fenotipico do nucleo com relacao ao peso ao nascimento, prolificidade e mortalidade nos anos de 2004 a 2008, e relaciona-los a outros dados observados no Semiarido e obtidos na literatura especializada. As medias obtidas corrigidas foram 1,89±0,09 e 22,8±5,9 kg, respectivamente para peso ao nascer e peso ao parto. Os resultados obtidos demonstram peso ao nascer abaixo das racas exoticas no Semiarido e de ecotipos brasileiros em menor risco de extincao (p.ex. Moxoto). As taxas de mortalidade e a prolificidade obtidas sao vantajosas em relacao as apresentadas por racas exoticas presentes no Semiarido, mas nao superiores aos demais tipos naturalizados. Estudos economicos devem estabelecer se a relacao entre tais caracteristicas implicam em eficiencia para o sistema produtivo.

Validation of a microsatellite panel for parentage testing of locally adapted and commercial goats in Brazil

Brazilian goats are generally kept in small herds and extensive rearing systems, mainly in the northeastern region of the country. Despite production improvement in recent years, the lack of pedigree control has affected genetic progress. This study aimed to validate a panel of 16 microsatellites for parentage testing in locally adapted and commercial goats breeds raised in Brazil, as well as to compare its efficiency with the panel recommended by the Brazilian Ministry of Agriculture, Livestock and Supplies (MAPA) in 2004. The number of alleles and expected heterozygosity (He) per marker ranged from four to 18, and from 0.051 to 0.831, respectively. Using all markers, 100% of parentage cases of the validation dataset were resolved with a strict confidence level of 95%. The 16 microsatellites panel showed adequate exclusion power (99.99%) and identity accuracy (99.99%). Suggestions for improvement of the marker panel endorsed by MAPA are provided.