Genetic polymorphisms of kappa casein gene and its association with milk and composition traits in cows: An updated meta-analysis

IF 0.8 Q4 GENETICS & HEREDITY

Meta Gene Pub Date : 2021-12-01 DOI:10.1016/j.mgene.2021.100948

Yogesh C. Bangar, Ankit Magotra, Ashish Chauhan, A.S. Yadav

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引用次数: 3

Abstract

The present meta-analysis was planned to summarize the frequency and effects of A and B alleles of kappa casein gene on milk yield and composition traits by using information of 5715 genotyped cows from 42 published studies (2000 to 2020). The common effect sizes for gene frequency and association were considered as proportion and standardized mean differences (SMDs). Four genetic models viz., additive (AA vs. BB), dominant (AA+ AB vs. BB), completely over dominant (AA+BB vs. AB) and recessive (AA vs. AB+ BB) were used to compare the potential of genotypes in terms of SMDs along with 95% confidence interval (CI) for lactation milk yield and composition traits (fat yield, fat percentage, protein yield and protein percentage). The inconsistency between studies was estimated by heterogeneity statistic (I²). Meta-analysis of allelic frequency under random effects model showed that allele A was predominant as 0.71 (95% CI: 0.65, 0.76) in all genotyped cows. It was significantly higher gene frequency in 1834 Bos indicus cows (0.82, 95% CI: 0.77, 0.88) as compared to 3881 Bos taurus/cross cows (0.67, 95% CI: 0.61, 0.73), with substantial level of heterogeneity (92.73% to 97.68%). The results of association analysis showed that SMDs under all genetic models had significance (P < 0.05) with fat percentage only, with non-significant of heterogeneity (P > 0.05) between studies. For other composition traits and lactation milk yield, non-significant SMDs were observed with low to moderate heterogeneity index. There was not any risk of publication bias as confirmed from Egger's test (P > 0.05). It was concluded that significant molecular marker (allele B) of kappa casein can be used to improve milk fat percentage in dairy cows.

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奶牛kappa酪蛋白基因的遗传多态性及其与牛奶和成分性状的关系:最新的荟萃分析

本荟萃分析利用2000 - 2020年42篇已发表的5715头基因型奶牛的资料，总结kappa酪蛋白基因A、B等位基因的频率及其对产奶量和组成性状的影响。基因频率和关联的常见效应量被认为是比例和标准化平均差异(SMDs)。采用四种遗传模型，即加性遗传(AA vs. BB)、显性遗传(AA+ AB vs. BB)、完全超显性遗传(AA+BB vs. AB)和隐性遗传(AA vs. AB+ BB)，对泌乳量和组成性状(脂肪量、脂肪率、蛋白质产量和蛋白质百分比)的smd和95%置信区间(CI)进行了比较。通过异质性统计(I2)估计研究间的不一致性。随机效应模型下的等位基因频率荟萃分析显示，A等位基因在所有基因型奶牛中占优势，为0.71 (95% CI: 0.65, 0.76)。1834头母牛的基因频率(0.82,95% CI: 0.77, 0.88)显著高于3881头母牛/杂交母牛(0.67,95% CI: 0.61, 0.73)，且异质性显著(92.73% ~ 97.68%)。关联分析结果显示，所有遗传模式下的SMDs均具有显著性(P <0.05)，异质性不显著(P >0.05)。其他成分性状和泌乳量均不存在显著的异质性，异质性指数为低至中等。Egger的检验证实，没有发表偏倚的风险(P >0.05)。由此可见，kappa酪蛋白的显著分子标记(等位基因B)可用于提高奶牛的乳脂率。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Meta Gene Biochemistry, Genetics and Molecular Biology-Genetics

CiteScore

1.10

自引率

0.00%

发文量

期刊介绍： Meta Gene publishes meta-analysis, polymorphism and population study papers that are relevant to both human and non-human species. Examples include but are not limited to: (Relevant to human specimens): 1Meta-Analysis Papers - statistical reviews of the published literature of human genetic variation (typically linked to medical conditionals and/or congenital diseases) 2Genome Wide Association Studies (GWAS) - examination of large patient cohorts to identify common genetic factors that influence health and disease 3Human Genetics Papers - original studies describing new data on genetic variation in smaller patient populations 4Genetic Case Reports - short communications describing novel and in formative genetic mutations or chromosomal aberrations (e.g., probands) in very small demographic groups (e.g., family or unique ethnic group). (Relevant to non-human specimens): 1Small Genome Papers - Analysis of genetic variation in organelle genomes (e.g., mitochondrial DNA) 2Microbiota Papers - Analysis of microbiological variation through analysis of DNA sequencing in different biological environments 3Ecological Diversity Papers - Geographical distribution of genetic diversity of zoological or botanical species.