Identification of allelic variants, differential expression, and in silico analysis of caprine serum lysozyme gene

Authors: NARENDRA KUMAR NAGPAL, PUSHPENDRA KUMAR, CHINMOY MISHRA, TUSHAR JYOTIRANJAN, TARUN KUMAR BHATTACHARYA, BHARAT BHUSHAN, ARJAVA SHARMA

Abstract: Serum lysozyme gene empowers the immune system due to its bacteriolytic property targeting peptidoglycan layer of cell wall. Polymorphs of serum lysozyme gene are reported to be significantly associated with disease resistance traits. Two different gene fragments viz. fragment I (275 bp) and fragment II (230 bp) of serum lysozyme gene were amplified and screened by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique to identify genetic variation in two different goat breeds (Barbari and Marwari) of India. The serum lysozyme activity of different genotypes and mRNA expression across the breed was also estimated. In fragment I, four genotypes (AA, BB, AB, and CC) and three alleles (A, B, and C) were identified. The CC genotype (frequency-0.44) and B allele (frequency-0.46) was found to be prevalent in the population. In fragment II, six genotypes (AA, BB, AC, AD, AE, and FF) and six alleles (A, B, C, D, E, and F) were identified. The AD genotype (frequency-0.44) and A allele (frequency-0.53) were found to be prevalent in the population. A significant difference (p ≤ 0.05) in mean serum lysozyme activity was found among different genotypes of fragment I in Marwari goat only. The genotypes of fragment II did not show any statistically significant effect on serum lysozyme activity. Relative quantification showed that nondescript animals had higher expression levels of serum lysozyme gene as compared to registered goat breeds. A single nucleotide variation was detected at 93rd position (G to A) of full-length coding sequence where guanine in Barbari goat was replaced by adenine in Black Bengal goat. The polymorphic nature of the serum lysozyme gene and its differential expression will help to establish the role of the lysozyme gene in the disease resistance mechanism.

Keywords: Allele, genotype, goat, lysozyme, PCR-SSCP

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