Evaluating Environmental Effects on the Expression of Genes in Saccharomyces cerevisiae during Adenine Biosynthesis (Lab Report Sample)

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Evaluating Environmental Effects on the Expression of ade1 and ade2 Genes in Saccharomyces cerevisiae during Adenine Biosynthesis
Abstract
Gene expression is influenced by several factors including gene-to-gene interaction and gene-to-environment interaction. In many occasions, a particular phenotype is exhibited from the expression of multiple genes. For instance, the growth patterns and coloration of yeast colonies is affected by the interaction of many genes and enzymes employed in the biosynthesis of adenine. Mutant strains of Saccharomyces cerevisiae show different phenotypes depending on the environment they are exposed to during their growth. This study investigates the effects of varying the concentration of environmental adenine and oxygen during the growth of adenine-requiring mutant strains of HB2 yeast variant by growing the yeast in MV and YED agar media. Evidently, growth of the study organism concentrated around the adenine-soaked disks with white colonies where the concentration of adenine is highest, with red to pink colonies around the edges of the media. Similarly, red colonies develop in YED media when environmental oxygen is deprived, with white colonies, which are either mutants outgrowing the red colonies or due to fermentation of sugars in the early stages of metabolism. This indicates the environmental influence on phenotypic expression of genes. This study is important as the results can be reproduced in therapeutic studies with regard to drug interaction with the genes to avert the occurrence or minimize symptoms. They can also be applied in industry and agriculture with respect to manipulating expression of desirable genes for sustainable development. Lastly, future studies should focus on understanding the biochemical mechanisms inducing environmental effects of sequencing, to illuminate on mutations that result in a change of phenotypes.
Introduction
The genetic makeup of an individual is largely influenced by differing environmental conditions, which directly affect their behavioral and physiologic phenotypes (Pierce 28). In essence, a gene–environment interaction has been shown to elicit itself physiologically and behaviorally with respect to the expressed phenotype irrespective of genotype (Smith and Kruglyak e83). In the recent past, studies have deduced that both environmental and physiological conditions synergistically elicit effects on individual genetic variants educed as phenotypic traits (Pierce 32). In eukaryotic organisms, gender is a major internal environmental factor that primarily affects development and phenotypic traits of different sexes. In the external environment, chemicals, light and temperature, as well as drugs are influential factors that may define which genes are expressed, and hence affect how an organism develops and expresses its phenotypic traits (Bartlett et al. 314). The extensive research conducted in the field of genetics, tends to show that in years to come people will be using gene sequencing in trying to solve problems that solely arise out of the modern sedentary lifestyle. Eventually, this will have a domino effect; in fact create a breakthrough with regards to the engagement of the genome and the environment in totality.
On a scientific perspective, the environment affects the human phenotype in gene expression. For example when the human body is near the equator, the more its skin pigment increases, this is because the altitude and the hemoglobin produced affect the skin pigment. Similarly, in yeast, their phenotype is affected by the environment; there is a thin line in yeast experiments compared to how the environment affects the human gene expression (Smith and Kruglyak e83).Moreover, explaining the molecular mechanisms behind gene–environment interactions in humans and other experimental systems is difficult. It is therefore, important to dig for better and explicit perspectives to understand these interactions in order to make quality, evidence-based and informed health choices and decisions based on their genetic profiles (Roy et al. 975). The use of lower eukaryotic organism has made it possible to make some assumptions in relation to human genomics (Storey et al. e267; Pierce 21). For instance, the study of gene–environment interaction has been enumerated using yeast transcripts. In a study conducted by Cohen in 2009 he concluded that when yeast was grown in different varying environments, spores were produced by the yeast at differential rates. The genes in Saccharomyces cerevisiae were used for the case study. The Saccharomyces cerevisiae yeast was sourced from vine yards and oak trees in North America.
In this study, the investigator explains the environmental effects in the expression of mutant genes ade1 and ade2 in exhibiting for well-defined traits controlled by a single gene. Basically, the AMP biosynthesis genes, which include the ADE genes, in Saccharomyces cerevisiae are activated by specific transcription factors, Bas1p and Bas2p (Pho2p) devoid of extracellular limpidness (Smith and Kruglyak e83; Choi and Kim 1609; Wei et al. 12825). Under normal circumstances, the biosynthesis of adenine is retrospectively regulated by using the end products, a regulation process occurring in two different levels including a negative feedback mechanism inhibiting the enzymes entailed in the pathway, and a synchronized subjugation of genes encoding the enzymes used in the pathway at transcriptional level (Arney and Fisher 4356). The later process may be influenced by the environment in which the fungi are growing. Therefore, this study aims at establishing the influence of the environment in the expression of the regulatory genes to aid biosynthesis of adenine in S. cerevisiae.
Problem Statement
In S. cerevisiae, the AMP biosynthesis is controlled directly by the ADE genes (Re´Bora et al. 2001). Ideally, yeasts manufactures adenine as a primary compound molecule in adenosine monophosphate from phosphoribosylpyrophosphate (PRPP), which is actually a sugar-phosphate compound (Dye, Turner and Ward 66; Choi and Kim 1611). The engagement between genes and environmental conditions has affected the phenotypic traits shown by organisms. In regards to S. cerevisiae, numerous genes and enzymes control the biosynthesis of AMP enabling the occurrence of mutation on any of the gene resulting to the impairment of the gene, either partly or wholly, eventually triggering the production of extra adenine to maintain the fungal growth (Wei et al. 12826; Roy et al. 976; Arney and Fisher 4356). Past studies on genetic research have concentrated mostly on the activation of AMP biosynthetic genes ignoring the environmental effect in gene expression (Dye et al. 68). The zone of this study is to ascertain the consequence of the environment in phenotype expression in yeast using HA1, HA2, HB1, and HB2 mutant strains.
Justification
In most instances, models are purposely used to explain genetic phenomena and relay them to show how the same phenomena are related in the human body and its physiology (Pierce 33). Historically, the interaction between gene and environment studies have existed for quite some time, however the workings of the phenomena in gene expression tends to pose a great difficulty in comprehending it. It is of paramount importance medically to comprehend the repercussions of trying to contain the threats posed by the environmental exposure in trying to lower the probability of being infected by the disease. In showing that some phenotypes are showcased in yeast because of the exposure to an environment that is subject to control by some condition can be extended to human beings to establish that they carry genes that show resistance or susceptibility to a diseased body subject to some environmental factors (Smith and Kruglyak e83). This study will be useful to various public health stake holders in devising ways and coming up with environmental interventions in prevention of diseases.
Study Questions
* What is the impact of differing, the centralization of adenine in the nature on quality outflow in the biosynthesis, and phenotype as far as color of the development of S. cerevisiae?
* What is the impact of fluctuating oxygen fixation in the nature's turf on quality outflow and phenotype of S. cerevisiae?
* Are there circumstances where same mutant strains would bring about a white phenotype?
Study Objectives
* General Objective
To establish if and how the environment influences gene expression and phenotype in S. cerevisiae
* Specific Objective
* To establish the impact of convergence of adenine in the environment in regards to gene expression in the biosynthesis and phenotype regarding the color change of S. cerevisiae in growth.
* To establish the effect of fluctuating oxygen fixation in the environment gene expression and phenotype of S. cerevisiae.
* To establish whether same mutant would form a white mutant.
Null Hypothesis
* There is no impact in changing adenine concentration in the environment on gene expression in the biosynthesis, and phenotype in regards to the color growth of S. cerevisiae.
* There is no impact of changing Oxygen fixation in the environment on gene expression and phenotype of S. cerevisiae.
* Similar mutant strains do not bring about a white phenotype.
Materials and Methods
In this study, two experimental procedures were used in which the first experiment was aimed at establishing the effects of varying the concentration of adenine in the environment on the expression of genes during the AMP biosynthesis and color of growth, which marks the exhibited phenotype. The second experiment was testing the effects of varying oxygen concentration in the environment on gene expression and phenotype exhibited by S. cerevisiae. Th...