Diversity among populations goats based on morphometric markers / Diversidade genética entre populações caprinas com base em marcadores morfométricos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The goats were introduced in Brazil by the Portuguese colonizers. Today it is difficult to accurately identify the origin of the Brazilian domestic animals and it is unknown the entire extent of its diversity. The conservation and breeding of domestic animals depend on diversity in the species concerned. Theobjectives of this study were 1. compare different multivariate techniques in the study of genetic diversity among and inside goats populations through morphometric characters; 2. phenotypically characterize the goats populations; 3. establish groups according to racial or geographical affiliation of individuals, for conservation or genetic improvement programs; 4. identify the most suitable crossbreeding for formation of compounds; 5. markers indicate the most discriminant. The biometric markers were used: shoulder height (AC), chest height (AP) ear length (CO), thorax depth (AC-AP) and indexes with two bodily measures. The morphological characteristics of known genetic inheritance were used for the presence or absence of reduced ears, horns, long hair, wattles, beard, roan color, brown eumelanin and eumelanic standard pigmentation. Biometric characters were sampled for 796 Brazilian and Moroccan goats. For phenotypic traits it was showed 21 different populations (n = 2938) goats in Brazil, Africa, Continental Europe, Mediterranean islands. The results for the morphological traits allowed grouped populations for its phenotypic similarities that for its history. The genetic distance for alelleque morphogical traits, applying the method developed by Nei (1972), was: least between goats from Saanen and Marota (0,0014), Boer and Azul (0,0069); and greatest between populations Sardinia and Nambi (0.5458). The SRD of Ceará and Piauí are similar to each other (D = 0,0532). In the dendrogram was the emergence of four branches. A composed exclusively of Nambi, the other goats in Sardinia and Malta. The third class was composed (83% of bootstrap) by exotic dairy breeds and the other ecotypes of Piauí. The fourth branch was formed by types Moroccan and other Mediterranean populations. The results (using the biometric measures) are in agreement with the historical and the geographical distribution of the populations. The junctions obtained in the dendrograms from the average Euclidean distance and e Mahalanobis of distance, is indicative of high similarity among dairy breeds of European and Drâa (Moroccan population). The cluster the Moroccan populations Zagora and Rhâali in the dendrograms denote that the geographical proximity of the two was more important than the relationship supposed between Drâa and Zagora populations. The goats Azul and SRD first grouped with the Zagora and Rhâali, and all those with the Anglo-Nubian and Boer. Nambi and Marota are types the part, Azul and SRD are next between itself . The inclusion of other genetic groups for comparative analysis, the use of more number markers and individuals will give greater accuracy in the study of genetic diversity. Through the analysis of principal components showed that the groups were partially consistent with the origin and history of populations. The spatial distribution of individuals, the main components, the genetic groups identified the most similar / dissimilar. Allowed, also show the degree of uniformity / imbalance between individuals within each population, therefore the type showed lower Blue standardization among the populations considered.

ASSUNTO(S)

grouping analysis genetic diversity recursos zootécnicos diversidade genética análise de agrupamento genetica e melhoramento dos animais domesticos zootechnical resourcey

ACESSO AO ARTIGO

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