High Resolution Melt Curve Analysis for the detection of A1, A2 β-casein variants in Indian Cows (original) (raw)
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Cellular and molecular biology (Noisy-le-Grand, France), 2016
There are two allelic forms of A1 and A2 of β-casein gene in dairy cattle. Proteolytic digestion of bovine β-casein A1 type produces bioactive peptide of β-casomorphin-7 known as milk devil. β-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 β-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 β-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 ...
Journal of Animal Science, 1999
We have optimized the polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) technique to screen the most frequent variants (A 1 , A 2 , A 3 , and B) of the bovine β-casein gene. Five partly overlapping PCR products (233, 234, 265, 466, and 498 bp) of Exon VII of the β-casein gene that encompass the target point mutations were heatdenatured, separated on nondenaturing polyacrylamide gels, and silver-stained. Simultaneous detection of all variants in reference samples of known genotypes
Analysis of beta-casein gene (CSN2) polymorphism in Tharparkar and Frieswal cattle
Indian Journal of Animal Research, 2019
A1 and A2 are most frequently observed Beta-Casein variants in dairy cattle. A1 â-casein on digestion releases an opioid, BCM-7 which has been found significantly associated with type 1 diabetes mellitus (DM-1), ischemic heart disease (IHD), autism and including other immune suppression activities in man. Whereas A2 â-casein is devoid of such adverse effects. The present study involved genotyping of 181 cattle of two breeds Viz., Tharparkar and Frieswal for genetic variants A1 and A2 beta casein gene by PCR-RFLP method using DdeI restriction enzyme. The results showed that the A1 and A2 allelic frequency as 0.04 and 0.96 in Tharparkar while in Frieswal (HF x Sahiwal), it was 0.37 and 0.63 respectively. The average genetic diversity (0.47), polymorphism information content (0.35) and effective allele number (1.87) reflected existence of medium genetic variability in tested population. The lower PIC value in Tharparkar cattle (0.073) indicates low genetic diversity whereas; moderate v...
Analysis of beta-casein gene (CSN2) polymorphism in different breeds of cattle
2014
The goal of work was identification of β - casein gene polymorphism in different breeds of cow. The beta - casein constitutes up to 45 % of the casein of bovine milk. The most common forms of beta-casein in dairy cattle breeds are A1 and A2, while B is less common. The β-casein A1 variant was associated with the incidence of diabetes mellitus 1st type, coronary heart disease and autism. The A2 variant reduces serum cholesterol. The material involved 287 cows (Simmental breed – 111 cows, Pinzgau breed – 89 cows, Holstein breed – 87 cows). Bovine genomic DNA was extracted from whole blood by using commercial kit and used in order to estimate β - casein genotypes by means of PCR-RFLP method. In the populations included in the study were detected all three genotypes – homozygote genotype A1A1, heterozygote genotype A1A2 and homozygote genotype A2A2 with frequencies 0.1261, 0.3333 and 0.5405 in Simmental breed; 0.1379, 0.4598 and 0.4023 in Holstein breed, 0.3034, 0.5168 and 0.1798 in Pin...
Defence Life Science Journal
Bovine milk is regarded as nature's perfect food due to presence of vital nutrients. However some peptides are generated after proteolytic digestion of β-casein that have opioid properties and may increase the risk of chronic diseases. There are 13 genetic variants of bovine beta-casein; out of these A1 and A2 are the most common in dairy cattle breeds. The A1 and A2 variants differ only at position 67, which is histidine in A1 or proline in A2 milk. Earlier published reports have indicated that A1 β casein could be responsible for several health disorders like diabetes, coronary heart disease etc. while A2 β-casein is generally considered safe for human consumption. In the present study, an effort was made to sequence characterize β casein gene and identify allelic distribution of A1A2 alleles in native cattle of Ladakh region adapted to high altitude and low oxygen condition. The data showed 2 non-synonymous variations in coding region, while 5’UTR was completely conserved. Th...
Status of β-casein ( CSN 2 ) Polymorphism in Frieswal ( HF X Sahiwal Crossbred ) Cattle
2013
Cow milk is a rich source of protein and selected micronutrients such as calcium. Recently, a relationship between disease risk and consumption of a specific bovine β-casein fraction either A1 or A2 genetic variants has been identified. Polymorphism at codon 67 of the beta-casein gene: CCT→CAT causes a substitution of amino acid proline (in A2 variant) by histidine (in A1 variant). The presence of histidine residue at codon 67 makes A1 variants exclusively vulnerable to gastrointestinal proteolysis digestion to release bioactive peptide, beta-casomorphin-7 (BCM-7) which has been implicated in potential risk of human cardiovascular disease, type 1 diabetes, atherosclerosis and sudden infant death syndrome. Furthermore, consumption of milk with A2 variant may be associated with less severe symptoms of autism and schizophrenia. Besides, A2 variant has also been reported to have positive relationship with milk production traits especially protein and milk yield. Considering the importan...
Indian Journal of Veterinary and Animal Sciences Research, 2018
ABSTRACT Milk is one of the primary protein diets of high biological value available to the human population. As bovine beta casein gene is highly polymorphic with functional implications, this study was designed to detect the beneficial A2 genotype in the native Umbalachery cattle breed. Genomic DNA was isolated from blood samples of Umbalachery cows and A1 and A2 variants were detected by Tetra ARMS polymerase chain reaction. It was observed that the A2A2 genotype frequency was 82% and that of A1A2 was 18%. The A1A1 genotype was not detected in Umbalachery cattle in the present study. It may be concluded that majority of the Umbalachery cows retain their original beta casein protein variant that produce safer A2 milk for human consumption and that Tetra ARMS PCR is an efficient and rapid method that allows detection of single nucleotide polymorphism of A1 and A2 variants of beta casein gene. Key Words: Beta casein, SNPs, Genotyping, Tetra ARMS PCR, Umbalachery cattle.
Amplification of the Bovine Beta Casein Gene-Relevance to Modern Human Health
Alleles A1 and A2 of the Bos taurus CSN2 gene are the most common in a number of dairy cattle breeds. A genetic variant of the bovine β-casein gene includes A1 and B which encodes a histidine residue at codon 67, resulting in potential liberation of a bioactive peptide, β-casomorphin, upon digestion. This is an opium family substance, and has been associated with a large number of clinical implications in humans. Study includes amplification of bovine β-casein gene and further differentiation of variants A1 and A2 beta casein in cows. Conventional PCR was done to amplify β-casein gene in three hundred and one specimens. Further eighty amplicons were sent for sequencing. From the sequenced data, 24 were A2 homozygous (A2A2), 11were A1 homozygous (A1A1) and 37 heterozygous (A1A2). Allele discrimination in cows will be significant for the farmers, breeding programmes as well as for dairy industries as the milk variant determination will predict the outcome of the beta casein variants w...
PCR Based Genotyping of Lulu Cattle of Nepal for A1, A2 Type Beta-caseins
Journal of Nepal Agricultural Research Council
Lulu is an indigenous breed of cattle (Bos taurus) found in high altitude regions of western Nepal. Population of Lulu cattle has been declining due to introgression with other exotic breeds to increase milk productivity. Here we aimed at finding potential approach for conserving Lulu cattle and its assets by studying the milk contents and investigating which variant of beta-casein protein is present in this breed. Beta caseins are an abundant protein in cow milk with A1 and A2 being the most common genetic variants of this protein. Consumption of A1 type of milk has numerous health-related complications whereas A2 type of milk has numerous human health promoting factors. We used restriction fragment length polymorphism (RFLP) for determining the A1 and A2 variant of beta casein in Lulu cattle. For performing DNA extraction, we collected (n = 18) blood samples of Lulu from Mustang and (n=17) Nepal Agriculture research council farm. The amplified fragments in 3% agarose at 251bp and ...
Journal of Dairy Research, 2000
Caseins constitute the main part of milk proteins. The genes for the four major types of casein (CN), αs1-CN, αs2-CN, β-CN and κ-CN, reside on < 220 kb of the DNA on bovine chromosome 6 (Threadgill & Womack, 1990). Two casein genes (Cn), β-Cn and κ-Cn, have been found to be associated with differences in milk production, cheese yield, protein content, quality and fat yield (Ng-Kwai-Hang et al. 1984). Lin et al. (1986) have estimated that the combined contributions of αs1-Cn, β-Cn, κ-Cn and β-lactoglobulin loci accounted for 8·9% of the total phenotypic variance in milk, 8·6% of that in proteins and 5% of that in fat yield. Six alleles of κ-Cn gene have so far been identified: κ-CnA, κ-CnB, κ-CnC, κ-CnE, κ-CnF and κ-CnG. The κ-CN protein is 169 amino acids long with varying regions at codons 136 and 148. The A variant has threonine (ACC) at codon 136 and aspartic acid (GAT) at codon 148, whereas the B variant has isoleucine (ATC) and alanine (GCT) at codons 136 and 148 respectivel...