Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, PO Box 339, Bloemfontein 9301, Republic of South Africa.
J Dairy Res. 2019 Aug;86(3):323-330. doi: 10.1017/S0022029919000414. Epub 2019 Jul 24.
This research paper addresses the hypothesis that comparative genomics can give a new insight into the functionality of casein genes with respect to the casein micelle. Comparative genomics is a rapidly emerging field in computational biology whereby two or more genomes are compared in order to obtain a global view on genomes as well as assigning previously unknown functions for genes. Casein genes are among the most rapidly evolving mammalian genes, with the gene products mainly grouped into four types (αs1-, αs2-, β- and κ-casein). Functionally, casein genes are central to the casein micelle, the exact structure of which is still a subject of intense debate. Moreover, and adding to this complexity, some mammals lack some of the casein genes, although casein micelles have been observed in their milk. This observation has prompted an investigation into the distribution of casein genes across a host of mammalian species. It was apparent from this study that casein gene sequences are very diverse from each other and we confirmed that many mammalian species lack one or more of the casein genes. The genes encoding β- and κ-caseins are present in most mammals whereas α-casein encoding genes are less represented. This suggests different mechanisms for casein micelle formation in different species as well as the functions that are assigned to each individual casein.
本研究论文提出了一个假设，即比较基因组学可以为我们提供有关酪蛋白基因在酪蛋白胶束方面的功能的新见解。比较基因组学是计算生物学中一个迅速发展的领域，通过比较两个或更多的基因组，我们可以获得对基因组的全局视图，并为以前未知的基因功能分配任务。酪蛋白基因是哺乳动物中进化最快的基因之一，其基因产物主要分为四种类型（αs1-、αs2-、β-和 κ-酪蛋白）。从功能上讲，酪蛋白基因是酪蛋白胶束的核心，其确切结构仍然是激烈争论的主题。此外，这种复杂性还增加了一些哺乳动物缺乏某些酪蛋白基因的情况，尽管在它们的乳汁中观察到了酪蛋白胶束。这一观察结果促使我们对一系列哺乳动物物种中的酪蛋白基因分布进行了调查。从这项研究中可以明显看出，酪蛋白基因序列彼此之间差异很大，我们证实许多哺乳动物物种缺乏一种或多种酪蛋白基因。编码β-和 κ-酪蛋白的基因存在于大多数哺乳动物中，而编码 α-酪蛋白的基因则较少。这表明不同物种中酪蛋白胶束形成的机制不同，以及每个酪蛋白所分配的功能也不同。
