Genetics vs. Epigenetics: Biological Definition and the Evidence

Introduction

Genetics and Epigenetics have assumed a vital position in biomedical research in recent years due to humankind’s desire to interpret and diversify microscopic organic information. Centered on heritable genome-functional variation studies which take place with no differences in DNA-sequence variations, Epigenetics provides fresh options for studying and analyzing health/disease phenotypic-plasticity which is not explainable through classic genetics. Epigenetic-mediators comprise DNA-methylation, histone-modifications as well as a number of non-coding- RNAs which, through chromatin-remodeling-complex conjunctions, express activity as well as regional genome-repression. This permits for the execution of genetic programs from particular genomes as a vital process-driving development/differentiation. Due to the fundamental position of gene/genome regulations, Epigenetic-dysregulations are most often linked with pathological diseases, especially cancer. Even though several genetic/Epigenetic underlying mechanisms have remained elucidating, studies on Epigenetics have high development-biomarker potentials and diagnostic/therapeutic translation. This paper will study genetics as it is supported by epigenetics pieces of evidence of existence or non-existence.

Biological Definition of Genetics

Genetics, biologically, is considered to be:

‘A branch…that deals with heredity, especially the mechanisms of hereditary transmission and the variation of inherited traits among similar or related organisms’ (McKusick 2010).

In other words, genetics constitutes a biological study field majoring in heredity and organisms’ resultant variation. It seeks the comprehension of DNA or Deoxyribonucleic-Acid (Which is a cellular molecule containing genetic-inheritance-data); genes-inheritable informational units regarding defined traits are based on the DNA; Chromosomes or DNA-constituting structures found in several living things cells (Vogel and Motulsky 2010). Biologically, genetics is applicable to Forensic-science; which entails applying sciences to law-specific-matters by DNA fingerprinting; in which case, skin samples, blood-sample, semen, as well as several other detective materials are made use of in proving or disproving the innocence of suspects. Genetics is equally applicable to the Human-Genome-Project which’s prime objectives comprise locating and identifying human genes.

Genetics has, in present society, has a more pronounced contribution to biology compared to related studies; especially, as identified in disease-cure, enhanced crop production, crime and crime identification, and much more. Studies have reviewed that:

The field of genetics is in the midst of a revolution, and at the center of this exciting (and, to some minds, terrifying) phenomenon is the realm of genetic engineering: the alteration of genetic material by direct intervention in genetic processes (Sarkar 2008).

Considering Agriculture, as an example, there is the transplant of genes from organisms to organisms in the production of Transgenic-plants/animals. The same is also made use of in the reduction of high-fat quantity in meat-producing cattle as well as protein increment in dairy cattle. Genetic engineering has also significantly bruise-watched vegetations and fruits for a prolonged lifespan.

There are few exceptions to the engineering nature of genetics; for instance, within the legal practices, fingerprint interpretation is vital and only utilizes an individual’s DNA which is distinct from another individual’s and may even be used for the determination of parenthood- which is applicable to crime detection. In an instance whereby biology-based samples (such as skin) are collected from crime incidences, there is high certainty for the determination of the crime as it would be tracked to a suspect with an amazing degree of exactness. Figure 1 below shows a strand of DNA.

A strand of DNA; the molecular basis for inheritance in organism (Omenn, 2011).
Figure 1. A strand of DNA; the molecular basis for inheritance in organism (Omenn, 2011).

Biological Definition of Epigenetics

Epigenetics expresses genetic heritable alterations and cell-phonotype in the DNA-sequence non-availability of alterations (Gelehrter et al. 2009). Gelehrter et al. have noted that:

‘While the genome generally remains uniform in all the different cells of a complex organism, the epigenome controls the differential gene expression in most cell types, silencing or activating genes, and defining when and where they are expressed’ (Gelehrter et al. 2009).

Talking about the molecule, the events mentioned by Gelehrter et al. generally have to do with modification of Chromatin and cytosine-methylation at CpG-dinucleotides. Chromatin basically comprises histones (H-2A, H-2B, H-3 as well as H-4). Andrews et al. (2010) have noted that the histones majorly constitute positively-charged Amino acids which unit available negatively-charged DNA molecules. It is noted that:

‘These histones coil DNA into nucleosomes, consisting of a core octamer of histones around which the DNA is wrapped’ (Andrews et al. 2010).

Rothstein (2009) has further notes:

‘The amino-terminal tail of each core histone extends out from the nucleosome and it contains residues that can be epigenetically modified’ (Rothstein 2009).

Therefore, a unification of histone/DNA is controlled by epigenetic mechanisms which incapacitate gene transcription through condensation of chromatins, and a subsequent activation during the opening of chromatins. An illustration is acetylation-of-histones-neutralization where the positive-charging and relaxation of structural chromatins permit gene transcriptions (Andrews et al 2010).

Numerous epigenetic mechanisms have been found applicable to gene-expression regulations; these include DNA-methylation, chromatin-remodeling, as well as complex-histone-modifications such as gene-expression acetylations. Khoury et al. 2011) has included:

‘phosphorylation for gene activation and repression (mainly through different families of methyltransferases, acetyltransferases, and deacetylases)’ (Khoury et al. 2011).

Additionally, a number of less-well-understood protein-modifications (such as Ubiquitination and Sumoylation) and other fast emergent epigenetic-process involve little non-coding-RNAs (referred to as micro-RNAs) control gene-functions as well as parental-expression developments at the time of germline-formation of sexes (McNicholl and Cuenco 2009). Figure 2 illustrates epigenetic mechanisms as related to health endpoints.

Figure 2. An illustration of epigenetic mechanisms as related to health endpoints.
Figure 2. An illustration of epigenetic mechanisms as related to health endpoints.

Addtionally, genomic-imprinting constitutes a typical epigenetic-modification which cumulates selective expression as identified by McNicholl and Cuenco:

‘…to the selective expression of only one allele of autosomal genes or differential methylated regions (DMR), depending on their parental origin’ (McNicholl and Cuenco 2009).

This suggests that rather than maternal/paternal DMR/alleles expressing themselves in equal proportions, their repression/expression is dependent on the choice of inheritace (either maternally or paternally). Figure 3 shows two main epigenetic-coded constituents- DNA-mythylation and Histone-modifiaction. The repression/expression of likely DMR/gene varies through male/female gametes from a generation to another. Majority of acknowledged imprinted-genes in the mammalians are clustered or notably proximal with one-another.

Shows two main epigenetic-coded constituents- DNA-mythylation and Histone-modifiaction (Rothstein 2009).
Figure 3 shows two main epigenetic-coded constituents- DNA-mythylation and Histone-modifiaction (Rothstein 2009).

The Epigenome Project

The Human-Epigenome-Project (as referred to as HEP) is geared towards the identification, cataloging as well as interpretation of genomewide DNA-methylation blueprints of the entire human genes which exist in distinct body tissues. Studies have noted that:

‘Methylation is the only flexible genomic parameter that can change genome function under the exogenous influence’ (Eaton et al. 2010).

From the studies, methylation composes of the major and perhaps missing link which connects genetics, diseases as well as environments broadly considered as playing leading roles in nearly the entirety of human-pathological etiology. The occurrence of methylation is natural and based on CpG-sequence-cytosine which has to do with the exact control of gene expressions. Ordinarily, methylated-cytosine makes necessary clear pattern-specifics for types of tissues as well as state-of disease. These Methylation-Variable-Positions (MVPs) constitute the commonest epigenetic markers. Likened to Single-Nucleotide-Polymorphisms 9SNPs), there is much hope for significant advancement of the understanding and diagnoses of human diseases.

The HEP comprises a private/public alliance that is driven by Huma-Epigenome-Consortium associates.

It has been noted:

The project set out to accomplish some intimidating goals: to identify human DNA’s 20,000 to 25,000 genes and to determine the sequences of the 3 billion chemical base pairs in DNA. In 2003, after 13 years of research, researchers completed this genomic map. Today, the project’s scientists continue to analyze the stored data — a job that will keep them busy for years to come (McNicholl and Cuenco 2009).

Evidence That Epigenetics Exists

Epigenetic evidence of existence precedes ARTs’ establishment and depends on increment in incidences of imprinting-disorder; a distinct gametes-emulation. Latest studies Olby (2009)) have suggested an induction in ovulation/oocytes which constitute minimal stable imprints that could be responsible for high rates of maternal-imprint malfunction observed by the studies.

There is also evidence of the existence of epigenetics through the realization that genetic functional history from a generation could sway its next-general expressivity. Considering somatic cells, genetic variations are most often linked with variations in cytosine-methylation patterns of DNA. Studies conducted recently stipulate:

‘…information about patterns of methylation and other epigenetic states can also be transmitted from parents to offspring’ (Khoury et al. 2011).

The evidence constitutes the backbone model for acquired-epigenetic-variation inheritances.

Evidence that Epigenetics Does not Exist

Evidence for the non-existence of Epigenetics has been discussed by Andrews et al. (2010) where the scholar has described the argument for the existence of evidence for epigenetics as:

‘central dogma’ of modern orthodox biology (and its centralization on the argument) that life is controlled by genes’ (Andrews et al 2010).

Cell-biologist Bruce Lipton has also explained that genetic-determinism is nothing else but a fundamental fawn. According to these arguments, studies on how cells collect and carry out a procession of information have illustrated:

‘…a cell’s life is controlled not by its genes but by the physical and energetic environment, which, in the case of humans, includes our thoughts’ (Andrews et al. 2010).

This argument, thus, discards the authenticity of evidence for the existence of epigenetics.

Conclusion

This paper has discussed genetics interlink with epigenetics pieces of evidence of existence or non-existence. Genetics and Epigenetics have assumed a vital point of concern in biomedical research in recent ages due to humankind’s desire to better interpret and diversify microscopic organic information. Centered on heritable genome-functional variation studies, the paper has considered DNA-sequence variations with an inclination to the fact that Epigenetics provides fresh options for studying and analyzing health/disease phenotypic-plasticity which is not explainable through classic genetics.

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