Genetic population structure of Brazilian bovine breeds inferred by RAPD markers (Estrutura genética de populações de raças bovinas brasileiras inferida por marcadores RAPD)

Serrano G.M.

Description

Resumo
Conservation and improvement strategies should be based on the association between genetic and phenotypic characteristics. In this study 10 different populations of five native Brazilian cattle breeds (Caracu, Mocho Nacional, Crioulo Lageano, Curraleira and Pantaneira) were characterized using RAPD techniques to estimate their genetic relationships and verify the existence of possible regional differences within each breed. Two commercial breeds were used as control and outgroup respectively (Holstein and Nellore). 120 arbitrarily primers were screened, of which 22 were selected, and generated 122 polymorphic bands. When all groups were analysed in pairs, non-significant genetic variability (p>0.05) observed only between two populations of Curraleiro breed located in States of Piaui (CUPI) and Minas Gerais (CUMG). Using Popgene program Nei"s 1978 genetic distance was estimated. The smallest divergences were observed between groups of the same breed and the least distance between the two groups of Caracu breed (0.0159). In the four populations of Curraleiro the groups CUPI and CUMG presented the smallest difference (0.0285). These results could indicate that these two populations have high genetic similarity. In the dendrogram generated by UPGMA method all groups clustered in their respective breed. In this study we could demonstrate the existence of regional genetic differences between the populations of native breeds. These estimates could be useful in crossbreeding and genetic sample exchange between different nuclei.
Abstract
Estratégias para a conservação e melhoramento animal devem ser baseadas na associação de características fenotípicas e genéticas. Neste estudo realizou-se a caracterização genética de 10 diferentes populações de cinco raças bovinas nativas brasileiras (Caracu, Mocho Nacional, Crioulo Lageano, Curraleira e Pantaneira) através da técnica de RAPD, visando estimar a relação genética das populações e verificar a possibilidade de existir diferenças regionais dentro de cada raça. Duas raças comerciais foram utilizadas como controle e outgroup respectivamente (Holandesa e Nelore). Uma triagem com 120 primers foi realizada dos quais foram selecionados 22, que geraram 122 bandas polimórficas. Quando todos os grupos foram confrontados em pares, a variabilidade genética não foi significativa (p>0,05) apenas para dois grupos da raça Curraleira localizados no estado do Piauí (CUPI) e no de Minas Gerais (CUMG). Utilizando o programa Popgene, foram estimadas as distâncias genéticas, através do método de Nei (1978). As menores divergências foram observadas entre os grupos da mesma raça e a menor delas foi encontrada entre os dois grupos da raça Caracu (0,0159). Entre as quatro populações da raça Curraleira, os grupos CUPI e CUMG apresentaram a menor diferença (0,0285). Este resultado indica que esses dois grupos possuem grande similaridade genética. Os grupos de cada raça se agruparam em clusters diferentes, pertencentes às respectivas raças no dendrograma gerado pelo método de UPGMA. Neste estudo pode-se demonstrar a existência de diferenças genéticas regionais nas populações das raças nativas. Estas estimativas podem ser utilizadas em cruzamentos e trocas de amostras genéticas entre os diferentes núcleos.

Sujets

• Conservation genetics

Informations

• Publié par: erevistas
• Publié le: 01 janvier 2005
• Nombre de lectures: 18
• Langue: English

Extrait

0,05) apenas para dois grupos da raça Curraleira localizados no estado do Piauí (CUPI) e no de Minas Gerais (CUMG). Utilizando o programa Popgene, foram estimadas as distâncias genéticas, através do método de Nei (1978). As menores divergências foram observadas entre os grupos da mesma raça e a menor delas foi encontrada entre os dois grupos da raça Caracu (0,0159). Entre as quatro populações da raça Curraleira, os grupos CUPI e CUMG apresentaram a menor diferença (0,0285). Este resultado indica que esses dois grupos possuem grande similaridade genética. Os grupos de cada raça se agruparam em clusters diferentes, pertencentes às respectivas raças no dendrograma gerado pelo método de UPGMA. Neste estudo pode-se demonstrar a existência de diferenças genéticas regionais nas populações das raças nativas. Estas estimativas podem ser utilizadas em cruzamentos e trocas de amostras genéticas entre os diferentes núcleos." />

GENETIC POPULATION STRUCTURE OF BRAZILIAN BOVINE
BREEDS INFERRED BY RAPD MARKERS
ESTRUTURA GENÉTICA DE POPULAÇÕES DE RAÇAS BOVINAS BRASILEIRAS INFERI-
DA POR MARCADORES RAPD
2 1 2 1Serrano, G.M. , A.A. Egito , C. McManus and A. da S. Mariante
1Embrapa Recursos Genéticos e Biotecnologia. Brasília-DF. Brasil. E-mail: [e-mail]
2Universidade de Brasília. Brasília-DF. Brasil. E-mail: [e-mail]
ADDITIONAL KEYWORDS PALAVRAS CHAVE ADICIONAIS
Bovine native breeds. Populations structure. Raças bovinas nativas. Estrutura de populações.
Conservation genetics. Conservação genética.
SUMMARY
Conservation and improvement strategies two populations have high genetic similarity. In
should be based on the association between the dendrogram generated by UPGMA method all
genetic and phenotypic characteristics. In this groups clustered in their respective breed. In this
study 10 different populations of five native study we could demonstrate the existence of
Brazilian cattle breeds (Caracu, Mocho Nacional, regional genetic differences between the
Crioulo Lageano, Curraleira and Pantaneira) were populations of native breeds. These estimates
characterized using RAPD techniques to estimate could be useful in crossbreeding and genetic
their genetic relationships and to verify the sample exchange between different nuclei.
existence of possible regional differences within
each breed. Two commercial breeds were used
as control and outgroup respectively (Holstein RESUMO
and Nellore). 120 arbitrarily primers were
screened, of which 22 were selected, and Estratégias para a conservação e mel-
generated 122 polymorphic bands. When all horamento animal devem ser baseadas na
groups were analysed in pairs, non-significant associação de características fenotípicas e
genetic variability (p>0.05) observed only genéticas. Neste estudo realizou-se a carac-
between two populations of Curraleiro breed terização genética de 10 diferentes populações
located in States of Piaui (CUPI) and Minas Gerais de cinco raças bovinas nativas brasileiras
(CUMG). Using Popgene program Nei's 1978 (Caracu, Mocho Nacional, Crioulo Lageano,
genetic distance was estimated. The smallest Curraleira e Pantaneira) através da técnica de
divergences were observed between groups of RAPD, visando estimar a relação genética das
the same breed and the least distance between populações e verificar a possibilidade de existir
the two groups of Caracu breed (0.0159). In the diferenças regionais dentro de cada raça. Duas
four populations of Curraleiro the groups CUPI raças comerciais foram utilizadas como controle
and CUMG presented the smallest difference e outgroup respectivamente (Holandesa e Nelore).
(0.0285). These results could indicate that these Uma triagem com 120 primers foi realizada dos
Arch. Zootec. 54: 409-414. 2005.
GeneticSerrano.p65 409 07/12/2005, 14:53SERRANO, EGITO, MCMANUS AND MARIANTE
quais foram selecionados 22, que geraram 122 conservation and improvement, that
bandas polimórficas. Quando todos os grupos these must be based on the combination
foram confrontados em pares, a variabilidade of the phenotypic and genetic data.
genética não foi significativa (p>0,05) apenas Studies related to the genetic
para dois grupos da raça Curraleira localizados characterization of the native Brazilian
no estado do Piauí (CUPI) e no de Minas Gerais bovine breeds are being carried out in
(CUMG). Utilizando o programa Popgene, foram the Laboratory of Animal Genetics -
estimadas as distâncias genéticas, através do Brasilia, DF – using DNA molecular
método de Nei (1978). As menores divergências markers. One of those molecular
foram observadas entre os grupos da mesma markers used is the RAPD (random
raça e a menor delas foi encontrada entre os dois amplified polymorphic DNA). The
grupos da raça Caracu (0,0159). Entre as quatro
RAPD metodology is being widely used
populações da raça Curraleira, os grupos CUPI
in studies on conservation, as it is
e CUMG apresentaram a menor diferença
realively simple, low cost and that does
(0,0285). Este resultado indica que esses dois
not require specific knowledge on thegrupos possuem grande similaridade genética.
population to be studied, helping in theOs grupos de cada raça se agruparam em clusters
choice of strategies to preservediferentes, pertencentes às respectivas raças
threatened species and breeds. Hereno dendrograma gerado pelo método de UPGMA.
these markers were used to study 10Neste estudo pode-se demonstrar a existência
populations of five native Braziliande diferenças genéticas regionais nas popu-
bovine breeds in order to investigatelações das raças nativas. Estas estimativas
the existence of regional geneticpodem ser utilizadas em cruzamentos e trocas
differences.de amostras genéticas entre os diferentes nú-
cleos.
MATERIAL AND METHODS
INTRODUCTION
In these study we analised possible
Brazilian native bovine breeds have regional diferences between Curraleiro
developed from those brought by the (CU) from the Northeast and Central
Portuguese soon after the discovery. West States; Caracu (CA) from Cen-
With importation of some exotic breeds, tral West and Southern Brazil and
mainly zebus, at the beginning of the National Polled breed (MN) from Mi-
past century, the native animals have nas Gerais State, South-eastern Brazil.
gradually been substituted making most Two other naturalized Brazilian cattle
of them threatened with extinction. breeds and two commercial breeds
Although the exotic breeds are were also studied. These included the
considered more productive, they do Pantaneiro (PAN, n=48) from the
not necessarily possess the adaptation, Pantanal region, South Western Brazil
resistance to illnesses and parasites and Crioulo Lageano (CL, n=48) from
found in the native breeds. Santa Catarina State, Southern Brazil.
The techniques for the analysis of As all native cattle breeds are of taurine
the genetic variability are essential origin the Holstein-Friesian (HOL,
ingredients for programs of rational n=48) was included as a control group
Archivos de zootecnia vol. 54, núm. 206-207, p. 410.
GeneticSerrano.p65 410 07/12/2005, 14:53GENETIC STRUCTURE OF BRAZILIAN BOVINE BREEDS
oand Nellore (NEL, n=48) ( Bos indicus) 1 min, 72 C for 2 min. A final extension
oas an outgroup. at 72 C was carried out for 7 min
oThe Caracu breed was divided in followed by a cooling at 4 C. PCR
two groups, in accordance with the products were separated by electro-
aptitude of the populations, the Caracu phoresis in 1.4 percent agarose gels in
Caldeano (CA1, n=17) selected for 1 x TBE, and were stained with ethidium
milk and the other collected in the bromide (0,6 mg/ml) and observed under
remaining portion of Brazil (CA2, n= UV light.
31), usually selected for meat pro- The fragment data were entered in
duction. The Curraleiro was divided in a computer file as a binary matrix: 0
four groups of origin and/or region of coded for absence and 1 for presence
the herd. The first group (CUPI, n=12) of a band. The genetic distances
was composed of animals from Piauí, between populations were calculated
the II group (CUMG, n=7) of Minas using the POPGENE program (Popu-
Gerais, and the other two were from lation Genetic Analysis) version 1.31
Goiás, group III (CUGO1, n=9) of (Yeh et al., 1999). This program
Maranhão origin and the IV group establishes standardized genetic
(CUGO2, n=2) from Natividade-GO. distance matrices (Nei, 1972) and
The National Mocho was divided in matrices of genetic distances corrected
two groups, in the first group (MN1, for small samples (Nei, 1978). All clus-
n=13) from the Três Barras Farm - ter analyses done in this work used
MG and the other (MN2, n=34) animals UPGMA and the resulting clusters
from the Bank of Animal Germplasm were expressed as dendrograms. The
located in Embrapa Recursos Gené- bootstrap analysis was carried out using
ticos e Biotecnoloiga, Brasília-DF. the TFPGA program (Tools for
DNA extraction was based on a Population Genetics Analyses, version
non-organic protocol described on 1.3) (Miller, 1997). The analysis of
Miller et al. (1988) with slight molecular variance (AMOVA) (Exco-
modifications. A total of 120 arbitrary ffier et al., 1992) was used to analyze
primers (Operon Technologies Inc., the variance between the populations.
Alameda, Calif.: A, B, E, J, K and AB)
were screened using one sample of
each breed. RESULTS AND DISCUSSION
Amplification reactions were
Of the 120 primers investigated, 72performed in 50mM KCl, 20mM Tris-
were polymorphic (60 percent), 23HCl (pH 8,4), 2,5mM MgCl, 200mM2
monomorphic (19,2 percent) and 25of each dNTP, 0,4mM primer, 9ng
did not amplify or had poor amplificationtemplate DNA, 8 percent of BSA (2,5
(20.8 percent). Only those thatmg/ml) and 1.5UI Taq DNA polimerase
presented at least 4 polymorphic bandsin a final volume of 13ml. DNA
amplification was performed in a were used, thus reducing, the time and
thermal cycler programmed as follows: th