Estrogen has an important function in swine reproduction and growth. A Pvu II restriction enzyme polymorphism has been proven to be an important genetic variation in the estrogen receptor gene (ESR) and may be considered as a candidate gene for use in pig production but there is no data regarding the prevalence of this polymorphism in the Brazilian pig population. We used DNA samples from the following three purebred pig breeds: Large White (336 females and 26 males), Landrace (304 females and 27 males) and Pietrain (125 females and 11 males). The ESR genotyping was performed using PCR-RFLP. For each breed, genotypes for the ESR gene were compared independently for expected progeny differences (EPD) in litter size (LS), average daily weight gain (DWG) (g/day) and back fat thickness (BT) as measured in mm by ultrasound. In the Large White breed, but not the other breeds, the ESR genotype was significantly (p < 0.05) associated to LS, DWG and BT. Large Whites genotyped as AA or AB had higher EPD values for the LS and BT traits compared to BB Large Whites, while AA Large Whites had higher DWG EPD values than BB Large Whites. Our results for the Large White population showed that the A allele has a beneficial effect on LS, DWG and BT expected progeny differences.

O aumento da produtividade e qualidade dos produtos animais vem se tornando de grande interesse econômico. A prolactina (PRL) é um hormônio essencial para o sucesso reprodutivo e seu receptor (RPRL) tem sido detectado em vários tecidos². O gene RPRL foi recentemente mapeado em suínos no cromossomo 16(6). Este trabalho teve como objetivo analisar a frequência genotípica do RPRL em três diferentes raças de suíno, Landrace, Large White e Pietrain e correlacionar os genótipos com características de interesse. Foram analisados um total de 124 animais. O DNA foi extraído de sangue total suíno e submetido a técnica de PCR-RFLP, para determinação do genótipo do gene do receptor da prolactina. As análises estatísticas mostraram que o genótipo RPRL teve efeito sobre peso médio diário na raça Landrace (p<0,0135). As médias de DEPGMD na raça Landrace também foram diferentes em relação ao genótipo (p< 0,0610), confirmando a análise dos dados reais de Ganho de Peso Médio Diário. Métodos de seleção assistida por marcadores, juntamente com métodos de seleção tradicional poderão ser utilizados para potencializar e acelerar o melhoramento de características de interesse econômico em suínos, onde o gene do receptor de prolactina (RPRL) poderá ser utilizado como um marcador molecular para o ganho de peso médio diário real e sua DEP.

The productivity and quality increase of the animal products is coming to be of big economic interest. The prolactin (PRL) is an essencial hormone for the reproductive sucess and its receptor (PRLR) has been detected in several tissues (Kelly et al., 1991). The PRLR gene has been recently mapped to pig chromosome 16 (Vincent et al., 1997).This research was aimed at analyzing the PRLR genotypical frequency in three different swine races, Landrace, Large White and Pietrain and correlate the genotypes with characteristics of economic interest. It was analyzed 124 animals. The DNA was extracted from the pig blood and submited to PCR-RFLP technique, to the genotypes determination of the prolactin receptor gene. The statistics analysis showed that the PRLR genotypes had an effect on the daily average weight of the Landrace race (p<0,0135). The averages of EDP (Expected Difference of Progeny) in daily average weight of the Landrace race were also different in relation to the genotypes (p<0.0610), confirming the real data analysis of daily average weight increase. Attended selection methods by markers, together with traditional seletion methods can be used to increase and accelerate the improvement of economic interest characteristics in pigs, while the prolactin receptor gene (PRLR) can be used as a molecular marker for the real daily average weight increase and its EDP.

Dois polimorfismos (GHC e GHD) no gene que codifica para o hormônio do crescimento foram determinados em um total de 96 animais de três raças de suínos (Pietrain, Large White e Landrace), através da PCR-RFLP. As freqüências alélicas observadas para GHC foram C1 0,42, C2 0,0, C3 0,06 e C4 0,52 para Landrace; C1 0,0, C2 0,03, C3 0,14 e C4 0,83 para Large White e C1 0,02, C2 0,25, C3 0,28 e C4 0,45 para Pietrain. Para GHD, as freqüências alélicas observadas foram D1 0,69 e D2 0,31 para Landrace; D1 0,25 e D2 0,75 para Large White e D1 0,72 e D2 0,28 para Pietrain.

Two polymorphisms (GHC and GHD) in the growth hormone gene were evaluated in the ninety-six (96) animals of three breeds of pigs (Pietrain, Large White, and Landrace), through PCR-RFLP. Allele frequencies observed for the GHC polymorphism were: C1 0.42, C2 0.0, C3 0.06 and C4 0.52 for Landrace; C1 0.0, C2 0.03, C3 0.14 and C4 0.83 for Large White and C1 0.02, C2 0.25, C3 0.28 and C4 0.45 for Pietrain. The GHD polymorphism presented the following allele frequencies:. D1 0.69 and D2 0.31 for Landrace; D1 0.25 and D2 0.75 for Large White and D1 0.72 and D2 0.28 for Pietrain.