RESUMO
There are two allelic forms of A1 and A2 of ß-casein gene in dairy cattle. Proteolytic digestion of bovine ß-casein A1 type produces bioactive peptide of ß-casomorphin-7 known as milk devil. ß-casomorphin-7 causes many diseases, including type 1 diabetes, cardiovascular disease syndrome, sudden death and madness. The aim of the present study was to determine the different allelic forms of ß-casein gene in Iranian Holstein, Simmental and native cattle in order to identify A1 and A2 variants. The blood samples were collected randomly and DNA was extracted using modified salting out method. An 854 bp fragment including part of exon 7 and part of intron 6 of ß-casein gene was amplified by allele specific polymerase chain reaction (AS-PCR). Also, the accuracy of AS-PCR genotyping has been confirmed by melting temperature curve analysis using Real-time PCR machinery. The comparison of observed allele and genotype frequency among the studied breeds was performed using the Fisher exact and Chi-squared test, respectively by SAS program. Obtained results showed the A1 allele frequencies of 50, 51.57, 54.5, 49.4 and 46.6% in Holstein, Simmental, Sistani, Taleshi and Mazandarani cattle populations, respectively. The chi-square test was shown that no any populations were in Hardy-Weinberg equilibrium for studied marker locus. Comparison and analysis of the test results for allelic frequency showed no any significant differences between breeds (P>0.05). The frequency of observed genotypes only differs significantly between Holstein and Taleshi breeds but no any statistically significant differences were found for other breeds (P>0.05). A relatively high frequency of ß-casein A1 allele was observed in Iranian native cattle. Therefore, determine the genotypes and preference alleles A2 in these native and commercial cattle is recommended.
Assuntos
Caseínas/genética , Alelos , Animais , Caseínas/metabolismo , Bovinos , DNA/isolamento & purificação , DNA/metabolismo , Éxons , Frequência do Gene , Genótipo , Íntrons , Irã (Geográfico) , Reação em Cadeia da Polimerase em Tempo Real , Temperatura de TransiçãoRESUMO
INTRODUCTION: Twin pregnancy is a high-risk pregnancy with different prevalences in different regions of the world which is on the rise due to growing use of assisted reproductive technology. The objective of this study is to determine the frequency of twin pregnancy and the neonatal outcome of these pregnancies. MATERIALS AND METHODS: This is a descriptive-analytic study conducted in 2004-2007 in Mo'tazedi Hospital, Kermanshah on 142 twin deliveries as well as the singleton deliveries before and after twin pregnancy as the control group. The required information, including maternal age, gestational age, newborn's gender, presentation of twins, birth weight, Apgar score, fetal anomalies, and neonatal mortality were extracted from medical files and analyzed statistically. FINDINGS: After assessment of 29,438 deliveries performed from 2004 to 2007, the frequency of twin pregnancy was found out to be 1 in 208 cases (48 %). The mean age of mothers was higher in twin pregnancies. The mean gestational age of twin pregnancy was 34.3 weeks. Apgar score and neonatal weight were significantly lower in twin pregnancy compared to singleton pregnancy (p < 0.001). Furthermore, visible anomalies and mortality were significantly higher in neonates born to twin pregnancies compared to singleton pregnancies (p < 0.0001 and p = 0.009, respectively). The ratio of male to female neonates was 1. CONCLUSION: This study indicated that twin pregnancy is a high-risk condition and entails greater neonatal complications compared to singleton pregnancy. Therefore, it is recommendable to have greater perinatal care and perform deliveries in well-equipped centers under supervision of an obstetrician.