Abstract
Modern dairy cattle breeding strategies depend on linkage analysis and quantitative trait loci (QTL) of genes involved in milk yield and composition. This is because of their biological desired quantitative traits that play key roles in milk production. In this study, three genes directly related to milk production: prolactin (PRL), bovine kappa-casein (K-CN) and the pituitary-specii¬c transcription factor (PIT-1) were analyzed in 144 cows. The aim of this study was to identify polymorphisms in the Holstein-Friesian cattle breed in Palestine in relation to the genetic markers and allelic variants of the three genes. Collection of samples depended on an experimental design that was completely randomized (CRD) and blood samples were collected from different cities across the West Bank, Palestine. The genotypes were determined through the polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP) technique. The amplified fragments of PRL (294-bp), K-CN (530-bp) and PIT-1 (451-bp) were digested with RsaI, HindIII and HinfI, respectively. Statistical analysis found that the prolactin allelic substitution (AG, GG) played a role in milk production with a p-value of 0.00643 and α (0.001**), the AG allele of PRL being more favorable for milk production as compared to the GG allele. Genetic variants of the bovine K-CN gene played a role in milk production with a p-value of 0.04071 and α (0.01*), the AA allele possessing more positive effect than the BB and AB alleles. Similarly, the allelic substitution of the PIT-1 gene affected milk production with a p-value of 2.274e-05 and α (0***), the AA allele exercising a more positive effect followed by the AB and BB alleles, respectively. Among the three studied breeds (Friesian, hybrid and local), results show that the Friesian breed possesses higher overall milk production in Palestine as compared to the other two breeds. Key words: Prolactin (PRL), bovine kappa-casein (K-CN), pituitary-specii¬c transcription factor (PIT-1), polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP).
Highlights
quantitative trait loci (QTL) analysis links two types of information, the phenotypic data and genotypic data in an attempt to explain the genetic basis of variation in complex traits (Kloosterman et al, 2010)
As a result of the recent advances achieved in genomics and molecular biology techniques and the completion of bovine genome sequence, whole cattle genomes can be screened for QTL using molecular maps to locate traits that can affect, for example, milk production (Kolbehdari et al, 2009)
This screening has proven critical for the identification of important traits that can provide linkages of phenotypic data with the genetic polymorphism of three genes associated with milk production in cattle (PRL, K-CN and PIT-1) (Kloosterman et al, 2010)
Summary
As a result of the recent advances achieved in genomics and molecular biology techniques and the completion of bovine genome sequence, whole cattle genomes can be screened for QTL using molecular maps to locate traits that can affect, for example, milk production (Kolbehdari et al, 2009). This screening has proven critical for the identification of important traits that can provide linkages of phenotypic data with the genetic polymorphism of three genes associated with milk production in cattle (PRL, K-CN and PIT-1) (Kloosterman et al, 2010)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
