Formerly International Journal of Basic and Applied Agricultural Research

Genetic variation of Beta-Lactoglobulin gene and its association with milk production in Sahiwal and crossbred cattle

A.K. GHOSH and R.S. BARWAL
Pantnagar Journal of Research, Volume - 20, Issue - 3 ( September-December 2022)

Published: 2022-12-31

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Abstract


Beta Lactoglobulin (β-Lg) is a major whey protein found in ruminant milk. This protein is found in various polymorphic forms some of which have been reported to bear a significant association with certain superior economic traits. Therefore, the present investigation was undertaken to detect polymorphism in β-Lg at the genic level. A total of 145 animals belonging to Sahiwal and crossbred were covered under the present investigation. DNA was extracted from the blood and was used to amplify a 398 bp fragment of β-Lg gene using polymerase chain reaction. The amplified fragment was subsequently digested using Hae III restriction enzyme. The restriction pattern so obtained was analyzed using 4% (w/v) agarose gel electrophoresis and was then visualized under UV transilluminator after staining with ethidium bromide. Three types of restriction patterns were seen in cattle. Genotype AA showed three (162, 137 and 99 bp long) fragments, genotype BB showed five (113, 99, 89, 73 and 24 bp long) fragments, while AB showed all seven (162, 137, 113, 99, 89, 73 and 24 bp long) fragments. Comparison with available database suggests that two of the restriction sites (at position 89 and 275) are polymorphic i.e., found in B but absent in A. Based on these observations genotypic frequencies of AA, AB and BB were found to be 0.43, 0.26 and 0.31 in Sahiwal and 0.44, 0.36 and 0.20 in crossbred, respectively. The allele frequencies of A and B were calculated from the genotypic frequencies and were found to be 0.56 and 0.44 in Sahiwal and 0.62 and 0.38 in crossbred cattle. The Analysis of variance and Chi-square test revealed no significant association between genotype and three lactation average milk productions in Sahiwal and crossbred cattle. AA genotype was found to produce more milk compared to other genotypes in Sahiwal and BB in crossbred. From the present investigation it can be concluded that polymorphism of β-Lg gene occurs in Sahiwal breed of cattle and has no significant role in milk yield.


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