USE OF TYPE I DNA MARKERS FOR INITIAL GENETIC CHARACTERIZATION OF TWO PORTUGUESE SWINE BREEDS(USO DE MARCADORES DE ADN TIPO I PARA LA CARACTERIZACIÓN INICIAL DE DOS RAZAS PORCINAS PORTUGUESAS)

Ramos A.M.

Description

Abstract
In order to be effective, strategies for conservation and improvement of local pig breeds must ideally include both the phenotypic and genetic characterization of those breeds. In this study, phenotypic information was collected for individuals from the Portuguese pig breeds, Alentejano and Bísaro. The DNA samples from these animals were then analyzed for variation at six type I loci to gain insight on the origin and integrity of these breeds. The detected variation at these loci was very low in the Alentejano and low to intermediate in the Bísaro. The association of each marker with a set of production traits was analyzed in the Bísaro. Results suggest that some of these genes may be associated with significant variation in these traits. Information derived from the characterization of local pig breeds at the molecular level may assist in conservation efforts and may also be used in future marker assisted selection programs.
Resumen
Para ser efectivos, las estrategias para la conservación y mejora de las razas porcinas locales deben incluir idealmente tanto su caracterización genética como fenotípica. En este estudio, la información fenotípica fue recogida de individuos pertenecientes a las razas portuguesas Alentejana y Bísaro. Las muestras de ADN de estos animales fueron entonces analizadas para la variación de 6 loci Tipo I para profundizar en el origen y la integridad de estas razas. La variación detectada en estos loci fue muy baja en el Alentejano y de baja a intermedia en el Bísaro. La asociación de cada marcador con una serie de caracteres productivos fueron analizadas en el Bísaro. Los resultados sugieren que algunos de estos genes pueden estar asociados con variaciones significativas de esos caracteres. La información derivada de la caracterización de las razas porcinas locales a nivel molecular deben apoyar los esfuerzos en conservación y deben también ser utilizadas en el futuro en programas de selección asistida por marcadores.

Sujets

• PIGS
• Biodiversity
• Molecular genetics
• Characterisation
• Cerdos
• Biodiversidad
• Genética molecular
• Caracterización

Informations

• Publié par: erevistas
• Publié le: 01 janvier 2003
• Nombre de lectures: 14
• Langue: English

Extrait

POSTER
USE OF TYPE I DNA MARKERS FOR INITIAL GENETIC
CHARACTERIZATION OF TWO PORTUGUESE SWINE BREEDS
USO DE MARCADORES DE ADN TIPO I PARA LA CARACTERIZACIÓN INICIAL DE DOS
RAZAS PORCINAS PORTUGUESAS
1,3 1 1 2 3 1Ramos, A.M. , R. Mestre, S. Gouveia, G. Evans, Y. Zhang, A. Cardoso,
3 2 1M.F. Rothschild, G. Plastow and T. Rangel Figueiredo
1Departamento de Zootecnia. Universidade de Trás os Montes e Alto Douro. Apartado 1013. 5000 911,
Vila Real. Portugal.
2PIC Group. University of Cambridge. CB2 1QP. UK.
3Department of Animal Science. 2255 Kildee Hall. Iowa State University. Ames, IA 50011. USA.
PALABRAS CLAVE ADICIONALESADDITIONAL KEYWORDS
Pigs. Biodiversity. Molecular genetics. Charac Cerdos. Biodiversidad. Genética molecular. Ca
terization. racterización.
SUMMARY RESUMEN
In order to be effective, strategies for Para ser efectivos, las estrategias para la
conservation and improvement of local pig breeds conservación y mejora de las razas porcinas
must ideally include both the phenotypic and locales deben incluir idealmente tanto su carac
genetic characterization of those breeds. In this terización genética como fenotípica. En este
study, phenotypic information was collected for estudio, la información fenotípica fue recogida de
individuals from the Portuguese pig breeds, individuos pertenecientes a las razas portugue
Alentejano and Bísaro. The DNA samples from sas Alentejana y Bísaro. Las muestras de ADN
these animals were then analyzed for variation de estos animales fueron entonces analizadas
at six type I loci to gain insight on the origin and para la variación de 6 loci Tipo I para profundizar
integrity of these breeds. The detected variation en el origen y la integridad de estas razas. La
at these loci was very low in the Alentejano and variación detectada en estos loci fue muy baja
low to intermediate in the Bísaro. The association en el Alentejano y de baja a intermedia en el
of each marker with a set of production traits was Bísaro. La asociación de cada marcador con una
analyzed in the Bísaro. Results suggest that serie de caracteres productivos fueron analiza
some of these genes may be associated with das en el Bísaro. Los resultados sugieren que
significant variation in these traits. Information algunos de estos genes pueden estar asociados
derived from the characterization of local pig con variaciones significativas de esos caracte
breeds at the molecular level may assist in res. La información derivada de la caracteriza
conservation efforts and may also be used in ción de las razas porcinas locales a nivel molecular
future marker assisted selection programs. deben apoyar los esfuerzos en conservación y
Arch. Zootec. 52: 255 264. 2003.RAMOS ET AL.
deben también ser utilizadas en el futuro en conservation efforts, there is also the
programas de selección asistida por marcado need to characterize local porcine
res. breeds at the morphological, genetic
and production levels, improve its per
formance and increase the value of the
INTRODUCTION breeds' typical products, by creating
protected quality marks. For this
Pig meat is a major source of protein purpose, sound and efficient breeding
for humans, accounting for approxima programs are needed, where DNA
tely 43 percent of the world productionmarker information may assist in the
of meat, according to the Food and selection of quantitative traits, including
Agriculture Organization of the United those that can be selected by traditional
Nations (FAO) statistics. A relatively means.
small number of breeds are used in There are two Portuguese indige
intensive pig production. This has led nous pig breeds, the Bísaro, located in
to an important decrease in registered the northeast part of the country, and
numbers of animals from local breeds, the Alentejano, reared in the southern
as these are frequently replaced by regions of Portugal. The census for the
improved breeds developed by mass Bísaro breed is presently of 850 adult
selection in large breeding programs individuals, while in the Alentejano 6000
and typically characterized by higher animals are registered in the herd book.
or more efficient production levels. According to the criteria established by
However, local pig breeds carry unique the FAO, the Bísaro is an endangered–
characteristics including for example maintained breed, while the Alentejano
adaptations to particular production is not at risk.
systems and environmental conditions. The Bísaro is a Celtic type breed,
Furthermore, these breeds still re considered to have originated from the
present the majority of the porcine European wild pig. The breed has been
population in several regions of the submitted to crossbreeding, with some
world. Nearly 46 percent of the world British breeds, such as Berkshire, Large
swine breeds are found in Europe. Black and Large White, in the first
thHowever, a large number of these decades of the 20 century (Vale,
breeds face the risk of extinction (FAO,1949) and also with Large White and
2000). The disappearance of these Pietrain in the last 30 years. Active
breeds would be an irreplaceable loss crossbreeding was eliminated only in
of a unique genetic heritage. The 1994, after the establishment of the
preservation of these local genotypes Breeders Association and the herd
is essential to guarantee the genetic book. The Bísaro is usually bred in
variability contained in these breeds small family herds, of no more than 10
for future generations. Such genetic pigs per farm, although recently some
variability may also increase in larger farms have also appeared.
importance as changes occur in The Alentejano is a Mediterranean
consumer demands, production systems type breed, related to the Spanish
and the environment. In addition to the Iberian pig. It is believed to have arrived
Archivos de zootecnia vol. 52, núm. 198, p. 256.TYPE I DNA IN PORTUGUESE SWINES
in the Iberian Peninsula along with theimportant traits. In this study, six genes
civilizations that invaded the Peninsula were chosen: calcium release channel
from the Mediterranean Basin (Delga (CRC1, also called the halothane gene),
do et al., 2001). Active crossbreeding prolactin receptor (PRLR), estrogen
has also occurred in this breed, but to receptor ( ESR), melanocortin 4 recep
a smaller extent. The breeding strategytor (MC4R), mast/stem cell growth
adopted for the Alentejano has been factor receptor ( KIT, the inhibition or
substantially different from the one dominant white locus) and melanocortin
registered in the Bísaro, since the 1 receptor (MC1R, known as the
introduction of foreign breeds has been extension locus controlling coat colour).
very limited. However, some crosses The objectives of this study were to
with British breeds, such as Berkshire, characterize the Bísaro and Alentejano
and to a larger extent with Landrace breeds using these type I DNA markers
(in the 1950s) have taken place (Frazão and to evaluate the effect of four of the
1984). The Alentejano is raised in markers (CRC1, PRLR, ESR and
medium to large size herds under MC4R) on birth weight, individual
extensive conditions, usually in open weaning weight and daily weight gain
range fields with cork trees. from birth to weaning.
Both the Bísaro and the Alentejano
are appreciated for their high quality
MATERIALS AND METHODSmeat, and are also the basis of the
production of several typical local pork
Animals: Blood and hair samplesproducts, which are increasingly in
were collected from individuals of thedemand by consumers. Thus, they
Alentejano and Bísaro breeds, in 11represent a very important source of
and 36 farms, respectively. The numberincome for the pig producers in Portu
of animals included in each markergal.
analysis varied (table I). For theThere are several tools available
association study conducted in thefor the genetic characterization of lo
Bísaro breed, all samples and datacal breeds. Microsatellites are recom
were collected in the University ofmended by FAO for the charac
Trás os Montes e Alto Douro pig farm.terization of genetic distances between
Individual birth and weaning weightbreeds (Barker, 1999). However, the
records were collected for Bísaroutility of type I DNA markers
piglets. In addition, average daily gain(polymorphisms in genes) has been
from birth to weaning was alsosuggested as an alternative (Ciobanu
et al., 2001). This type of marker calculated, as weight gain from birth to
offers the possibility of using marker weaning divided by the piglet weaning
information in the improvement of age. In the statistical analysis, adjusted
performance of any breed or population. values of weaning weight were used.
Marker assisted selection can be used Markers and genotyping: PCR
as a complement to the traditional RFLP (Polymerase Chain Reaction –
selection methods, in order to increase Restriction Fragment Length Polymor
the rate of genetic gain in economically phism) procedures were used to detect
Archivos de zootecnia vol. 52, núm. 198, p. 257.RAMOS ET AL.
Table I. Number of animals genotyped and allelic frequencies of four of the analyzed loci.
(Número de animales genotipados y de frecuencias alélicas de c