An Introduction Into The Study of Genetics
By: Eric Wang, Jason Jiang, Qixian Tao
Basic Information
The study of genes and general heredity is known as genetics. It is a centuries-old branch of biology that has greatly advanced our understanding of how features are inherited by subsequent generations. Numerous significant discoveries — including the identification of genes, the basic components of heredity, and the discovery of DNA — have resulted from the study of genetics. Discoveries in the intriguing science of genetics could lead to the solving of numerous puzzles about our surroundings.
The study of heredity, variation, and inheritance is included under the broad umbrella of genetics. It deals with the molecular mechanisms underlying the inheritance of features from one generation to the next. The gene, a section of DNA that codes for a particular trait, is the fundamental building block of heredity. Chromosomes are lengthy strands of tightly coiled DNA that are packed to organize genes. There are 23 pairs of chromosomes in humans, making 46 chromosomes in total. Numerous significant discoveries have resulted from the study of genetics, including the identification of genes — the basic building blocks of heredity — and the discovery of DNA, the molecule that makes up genes.
Animals possess a wide variety of genes, which are essential in defining the features and attributes of individual species. For instance, in many animals, including humans, the MC1R gene produces melanin, the pigment that gives hair, skin, and eyes their color. Differences in skin and hair colors as well as an increased risk of developing specific forms of skin cancer can result from variations in this gene. The FOXP2 gene is an additional instance, as it plays a role in the development of speech and language in both humans and other animals. Human speech and language impairments have been linked to mutations in this gene. These are but a handful of the numerous genes that have been discovered.
Phenotype describes the physical traits that arise from gene expression, whereas genotype describes an organism’s genetic composition. Numerous factors, including as environmental circumstances and epigenetic alterations, influence the intricate link between genotype and phenotype.
The process of using a gene’s encoded information to create a functioning gene product, like a protein, is known as gene expression. Numerous processes, including transcription, RNA processing, translation, and post-translational modification, are involved in the regulation of gene expression.
One can comprehend the correlation between phenotype and genotype by referring to the fundamental principle of molecular biology, which posits that DNA is converted into RNA and subsequently translated into a protein. The structure and function of a protein are determined by the amino acid sequence found in it, which is derived from the sequence of nucleotides in DNA. A protein’s amino acid sequence can be changed by mutations in its DNA, which can impact a protein’s function and result in phenotypic alterations.
Both humans and animals have vastly different numbers of genes. At first, the Human Genome Project calculated that humans possessed approximately 100,000 genes that code for proteins. Subsequent studies, however, have lowered this estimate downward to 20,000–25,000 genes.
The quantity of genes varies among other species. For instance, with 31,000 genes, the water flea Daphnia possesses the most genes known to science. With about 23,000 genes, mice, roundworms, and the tiny flowering plant Arabidopsis thaliana all have a similar amount of DNA as humans.
It is noteworthy that an organism’s complexity or evolutionary progress is not always correlated with its gene count. For instance, the genome of an amoeba is more than 200 times larger than that of a person, while having only 14,000 genes.
CRISPR and its Revolutionary Gene Editing Capabilities
A game-changer in the field of biotechnology, CRISPR is a gene-editing technique. It significantly reduces the difficulty of genetic engineering by enabling scientists to cut any desired genetic sequence. Bacteria use the CRISPR-Cas system as a defense mechanism against viral intruders. By enabling scientists to cut any desired genetic sequence with a few tweaks, CRISPR significantly reduces the difficulty associated with genetic engineering.
The process of cutting and rejoining DNA molecules to make new gene combinations is known as gene splicing. It’s a long-standing method employed in biotechnology and genetic engineering. In addition to improving the precision and efficiency of genome engineering, CRISPR technology has also been applied to regulate RNA splicing, the process by which messenger RNA is altered to generate distinct protein isoforms.
CRISPR technology has been applied to the treatment of illnesses like sickle cell anemia and holds great therapeutic promise. The proper application of this technology is a topic of continuous discussion, but there are also worries over the ethical ramifications of gene editing.
Since the technology is still in its infancy, questions have been raised concerning mosaicism — when some cells have the edit but others do not — and the impact of misplaced modifications. CRISPR safety is a major concern, and many people think that it shouldn’t be utilized for clinical reproductive purposes until further study has proved it is safe.
However, using CRISPR in medical settings would be an example of its application to benefit society. For instance, researchers at the University of Pennsylvania are exploring the use of CRISPR in the treatment of multiple myeloma, a bone marrow and blood cancer.
Zinc finger nucleases (ZFN), transcription activator-like effector nucleases (TALENs), and modified meganucleases are other gene-editing methods. These methods have been applied to genome editing, including the creation of genetically engineered crops and the management of hereditary illnesses.
ZFNs, for instance, have been utilized to produce genetically modified crops that are resistant to pests and herbicides. Animals that have been genetically altered through the use of TALENs include pigs that are resistant to African swine fever. Therapeutic applications for engineered meganucleases include the treatment of genetic illnesses including sickle cell anemia and beta-thalassemia.
Mutations
Mutations are alterations to a gene’s DNA sequence. They can happen in a number of ways, including when nucleotides are added, removed, or substituted. An organism’s genes and proteins may be significantly impacted by these modifications.
- Impact on Genes: Mutations have the ability to modify a gene’s function by influencing the type of protein that is made, as well as the quantity and timing of that production. Certain mutations can turn on a gene and increase the production of a protein, whereas other mutations can turn a gene off and reduce or stop the creation of proteins.
- Impact on Proteins: A mutation in the DNA sequence can alter the amino acid sequence of the protein because the nucleotide sequence of a gene dictates the amino acid sequence of the protein it codes for. The structure and function of the protein may be impacted by this.
For example, a mutation might:
- Cause the protein to fold incorrectly, rendering it nonfunctional.
- Change the protein’s active site, altering its ability to bind to its substrate.
- Create a premature stop codon, leading to a truncated protein that may not function properly.
Types of Mutations:
There are several types of mutations, including:
- Silent mutations, which do not change the amino acid sequence of the protein and are often neutral.
- Missense mutations, which change one amino acid in the protein, potentially altering its function.
- Nonsense mutations, which create a premature stop codon, leading to a truncated protein.
- Frameshift mutations, which are caused by insertions or deletions of nucleotides and can drastically change the protein’s amino acid sequence.
It is crucial to remember that not every mutation has negative effects. While some mutations may not affect the organism at all, others may be helpful and result in new variations that might be useful in particular situations. Nevertheless, a lot of mutations can be harmful and result in illnesses or problems. For instance, it is well known that mutations in the BRCA1 and BRCA2 genes raise the risk of ovarian and breast cancer.
Conclusion
In summary, genetics is a broad and intriguing subject that has fundamentally changed how we think about life. Genetics offers the framework for comprehending the diversity and complexity of life on Earth, from the fundamentals of heredity to the intricate processes of gene expression.
There is still a lot to learn in this discipline, despite the amazing advancements that have been accomplished. The fact that an organism’s complexity or evolutionary history is not always reflected in its gene count serves as a reminder of the complex and diverse nature of life.
We are continuously reminded of our connection to all life and the common genetic history that unites us all when we investigate the genetic blueprints of diverse creatures, ranging from humans to amoebas.
Genetics has a bright future ahead of it, with possible advances in agriculture, medicine, and environmental preservation. We are getting closer to comprehending the basic question of what it means to be alive as we continue to solve the riddles surrounding DNA.
This is the promise and potential of genetics: a science that not only explains our identity but also has the ability to influence our destiny.
Refenrences:
Wikipedia contributors. (n.d.). Genetics. In Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Genetics
Britannica, T. Editors of Encyclopaedia (n.d.). Genetics. In Encyclopædia Britannica. Retrieved from https://www.britannica.com/science/genetics
Centers for Disease Control and Prevention. (n.d.). Basics about Genomics. Retrieved from https://www.cdc.gov/genomics/about/basics.htm
Basic Biology. (n.d.). Introduction to Genetics. Retrieved from https://basicbiology.net/biology-101/introduction-to-genetics
National Human Genome Research Institute. (n.d.). Comparative Genomics Fact Sheet. Retrieved from https://www.genome.gov/about-genomics/fact-sheets/Comparative-Genomics-Fact-Sheet
(2018). BMC Biology, volume number. https://doi.org/10.1186/s12915-018-0564-x
National Human Genome Research Institute. (n.d.). A Brief Guide to Genomics. Retrieved from https://www.genome.gov/about-genomics/fact-sheets/A-Brief-Guide-to-Genomics
Genetics Digest. (n.d.). How Many Genes Do Humans Have? Retrieved from https://www.geneticsdigest.com/how-many-genes-do-humans-have/
Britannica, T. Editors of Encyclopaedia (n.d.). CRISPR. In Encyclopædia Britannica. Retrieved from https://www.britannica.com/technology/CRISPR
BrainFacts.org. (2019). CRISPR Explained. Retrieved from https://www.brainfacts.org/In-the-Lab/Tools-and-Techniques/2019/CRISPR-Explained-071519
National Human Genome Research Institute. (n.d.). Ethical, Legal and Social Implications. Retrieved from https://www.genome.gov/about-genomics/policy-issues/Genome-Editing/ethical-concerns
