Essential Genes: Definition, Overview, Meaning, Examples, Topics
Essential genes are the most important genes that are required for the growth and reproduction of the organism in a certain environment. The essentiality of a gene is dependent on the circumstances in which an organism lives. For example, a gene required to make a starch-digesting enzyme is only essential if starch is the only source of energy.
- What are Essential Genes?
- What are Genes?
- Essential vs. Non-essential Genes
- Characteristics of Essential Genes
- Role of Essential Genes in Development and Survival
- Human Essential Genes
- Recommended video for "Essential Genes"
- MCQs on Essential Genes
There have been attempts made to identify those genes that are required to maintain life, making sure all nutrients are available. Essential genes of single-celled organisms have proteins for basic functions, including genetic information processing, cell envelopes and energy production. These genes function to maintain a central metabolism, DNA replication, and translation of the mRNA. Essential genes are an important topic in the biology subject.
What are Essential Genes?
The essential genes can also be defined as the genes which are indispensable for the successful existence and reproduction of an organism. These genes are actualy proteins or RNA molecules required for important biological activity including; metabolism, mitosis, and DNA repair.
Essential genes are very important in biology as they aid in figuring out the parts fundamental for life forms, and are used as primary objectives for genetic and medical research. This article will therefore establish the concept of essential genes in the context of cell and organism health, the relevance of studying them in genetics and medicine, and an overview of the topic.
What are Genes?
Genes are the parts of DNA that are transcribed into mRNA and then finally translated into proteins. A gene is composed of nucleotides, which are sectioned into coding segments (exons) and non-coding segments (introns), and regulatory segments that determine gene expression.
Function of Genes in Living Organisms
Another function it has is in the construction and sustaining of an organism by the formation of proteins. These proteins offer several functions, including chemical reaction control, structural support, and function control. They are absolute necessities in the processes of growth, development and total organism functioning.
Essential vs. Non-essential Genes
The essential genes are those which can directly impact on survival of an organism and its ability to reproduce. These take part in important physiological processes, including metabolic processes and cell division.
The non-essential genes are those genes which are not essential to the organism’s existence, but can be beneficial to its survival in certain conditions, or increase its fitness.
Examples of each type
Essential Genes: Some of them are the TP53 gene, which plays a role in DNA repair as well as tumour suppression. The G6PD gene is significant for the performance of erythrocytes (red blood cells).
Non-essential Genes: For instance, some deal with colouration or odour or other features like genes that determine the colour of flowers in a plant, and the colour of the eyes and hair of a human being, among others. Even though they determine some aspects of life, they are not fundamental or vital.
Characteristics of Essential Genes
A gene that is necessary for the existence of the organism and its reproductive capability is essential. The first condition that defines an essential gene is the fact that the absence or any type of mutation of such a gene will carry a lethal or near-lethal consequence on the organism.
Functions of Essential Genes
Housekeeping genes are usually linked with some of the most basic cellular activities, including the Replication of DNA, transcription, translation, and cell division.
Essential genes typically perform critical functions necessary for life, including:
Metabolism: Genes that are crucial for the basic cellular functions, which include: the generation of energy through cellular respiration and the metabolism of nutrients that are ingested by the body.
Cell Cycle Regulation: A set of genes that determines how the cell will divide and how the genetic material should be duplicated.
DNA Repair: Genes that restore damaged DNA, thus helping in genetically stabilising the population.
Protein Synthesis: Genes corresponding to aspects of the translational apparatus, including ribosomal proteins and transfer RNAs (tRNAs).
Examples of essential genes in various organisms:
In Humans, the TP53 gene is very important in preventing the formation of tumours and repairing DNA. Defects in this gene have been shown to cause cancer, among other deadly diseases.
In Yeast, one of the genes essential for cell cycle regulation has been identified as the CDC28 gene. It expresses a kinase that aids in the regulation of the cell division process.
In Bacteria, these include the genes for the ribosomal Regulation,e.g., the 16S rRNA. These are part of the ribosome and are important for translation.
In Plants, the MADS-box genes are very important genes required for the formation of floral organs and also for sexual reproduction. A single gene can affect the development of flowers.
Role of Essential Genes in Development and Survival
Essential genes play a vital role in the functioning of an organism. They help in the regulation cell cycle for the development of an organism. The role of the essential genes is described below-
Role in Cell Cycle Regulation
Some genes are considered crucial for regulating the cell cycle, and they code proteins such as cyclins and CDKs. These genes also have the function of making correct cell division and avoiding cancer by controlling cell division and reproduction.
Role in Metabolic Pathways
Conserved genes underlie the products that control basic metabolic processes, that is, energy generation and nutrient assimilation. For example, the G6PD gene is described and plays a role in red blood cell glucose metabolism.
Role in Organism Development
The vital genes are significant for the correct formation of an organism. They control such functions as cell differentiation and tissue development. For example, at least one Hox gene controls the body plan construction in animals, and LEAFY controls the formation of flowers in plants.
Human Essential Genes
Essential genes hold a very great importance in the functioning of a person’s cellular processes. The importance of essential genes is described below-
Importance in Human Health and Disease
Housekeeping genes are involved in the significant biological process of health or the individual well-being of an organism. They take part in cellular activities, growth and regulation of energy production processes in the body. These genes, therefore, have to perform the right functions for growth and to prevent diseases.
Examples of Essential Genes in Humans
TP53: Codes a tumour suppressor protein to control cell division and DNA repair to avoid the formation of tumours and hence cancer.
G6PD: Carries an enzyme for the red blood cells that is vital in glucose metabolism, which aids in combating cases of hemolytic anaemia.
BRCA1: Participates in DNA repair; genetic alterations raise the risk of breast and ovarian cancer.
Impact of Mutations in Essential Genes
Some of the mutations are formed in the essential genes, and afterwards, the health of an organism can significantly deteriorate. That is, a change in gene TP53 may lead to the development of cancerous tissues and tumour growth. G6PD under oxidative stress can lead to hemolytic anaemia as experienced by people with G6PD mutations. Genes such as BRCA1, when altered, place one at a higher risk of getting certain types of cancer; it is for this reason that these genes are noticed to be central to the health of any organism.
Recommended video for "Essential Genes"
MCQs on Essential Genes
Q1. Read the following statements
STATEMENT i): Housekeeping genes are essential genes.
STATEMENT ii): A good example of dominant lethal alleles that are seen in humans is the rare Huntington’s disease.
Choose the correct option:
Option 1: Statement (i) is correct and statement (ii) is incorrect
Option 2: Statement (i) is incorrect and statement (ii) is correct
Option 3: Both statements are wrong
Option 4: Both statements are correct
Correct answer: 4)Both statements are correct
Explanation:
Statement i) is correct because, In molecular biology, housekeeping genes are typically constitutive genes that are required for the maintenance of basic cellular function, and are expressed in all cells of an organism under normal and pathophysiological conditions. That is why Housekeeping genes are essential genes.
Statement ii) is also correct because dominant lethal genes are the alleles whose presence is required in one copy in an entity for them to turn fatal. A good example of dominant lethal alleles that is seen in humans is the rare – Huntington’s disease. It is a neurodegenerative disorder which results in death.
So both of the given statements are correct.
Hence, the correct answer is option 4) Both statements are correct.
Q2. Alleles that produce a non-functional and harmful lethal allele by a mutation in an individual is
Option 1: Dominant lethal allele
Option 2: Essential allele
Option 3: Recessive lethal allele
Option 4: None of these
Correct answer: 2)Essential allele.
Explanation:
A gene that is required for an organism to survive is referred to as an essential allele. A person may become lethal if a mutation in an essential gene results in a damaging and non-functional allele; this means that the person cannot survive without the functioning form of the gene.
The development or operation of an organism depends on essential alleles. A deadly consequence may result from a mutation in these genes, particularly if the gene product (protein) is rendered inoperable.
Conversely:
Alleles that cause mortality under particular inheritance patterns (dominant or recessive) are sometimes referred to as dominant lethal alleles and recessive lethal alleles.
One way to think of essential alleles is as the essential genes needed for normal functioning.
Hence, the correct answer is option 2) Essential allele.
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Frequently Asked Questions (FAQs)
Observations of essential genes involve gene types that are indispensable to the organism and are involved in critical processes, for instance, cell division, nutrient processing, and DNA fixing.
Essential genes are genes that are critical for an organism's survival and basic cellular functions. They encode proteins necessary for fundamental processes like DNA replication, cell division, and metabolism. Without these genes, an organism cannot survive or reproduce.
From genetics studies and experiments such as gene knockout they are figured out by analyzing the effects that deficiency of a certain gene will result in lethal or severely negative consequences; and observing the existing physical functioning of a gene in model organisms.
Core genes are those genes, which are imperative for organisms because these genes are responsible for fundamental physiological processes and health. The proper functioning of the organs is vital in the fight against diseases as well as the development of an organism.
For instance, TP53 is concerned with the rate of cell division and, therefore, carcinogenesis; while G6PD has a role in glyceraldehyde phosphate dehydrogenase, and BRCA1 is concerned with DNA repair and is associated with genetic cancer predisposition.
Essential gene mutations have an effect that will lead to different health complications due to the disruption of essential body functions. For example, in the case of TP53 which may lead to cancer, G6PD which leads to hemolytic anemia and BRCA1 which increases the risk of developing breast and ovarian cancer.
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