Genetics is a special area of Biology which focusses on the basis of heredity (inheritance). Heredity is related to the transmission of genes from one to the next generation. Johann Gregor Mendel, a priest cum scientist, through his work on pea plants, discovered the fundamental laws of heredity and he is called the father of modern genetics. He proved that some factors (units of inheritance) in pairs are inherited as distinct units, one from each parent (Father and Mother). Mendel traced back the segregation of parental genes and their appearance in the offspring as dominant or recessive traits. He also established that this genetic transmission is not random, but follows a mathematical pattern of inheritance from one generation to the next (1). The factor (units of inheritance) described by Mendel, through subsequent researches, has been proved to be genes which all animals inherit from their parent.
Every life on earth is unique and this uniqueness is brought by genes. Human has approximately 25,000 genes. These 25, 000 Genes control your appearance (structure) and functions (what you do at every moment) (2). Life is made of cells (primary unit) and as an example, one human body in average contains approximately (35 – 40) trillion cells depending upon the body size. And all these cells at their centre (called nucleus for a higher form of life and nucleoid for a lower form of life) stored a chemical called DNA (Deoxyribonucleic acid) and genes are made of this chemical DNA. Genes are arranged inside the nucleus with a structure called chromosomes. Humans have 23 pairs of chromosomes and genes are located in the chromosome in pairs (two copies).
The composition of each gene usually changes over the times which is called mutation. Even new genes are created by several genetic processes (e.g., Duplication, Fusion and Fission, lateral gene transfer etc.). Scientists have also developed the method of isolating and modifying the genes in the laboratory, (called as Genetic Engineering) and make use of the derived engineered genes to develop industrial, agricultural, medical, and other technological applications (emerged as a subject called Biotechnology).
Apart from the tremendous diversification of the discipline Genetics, currently the knowledge of human and clinical genetics have generated renewed interest mainly because knowledge of the variation of human genes is helping to study the role of genetic factor in the development of human diseases and better management procedure of the disease towards a cure. Quite a few human diseases are manifested due to critical mutation incurred in the genes, lifestyle choices and living environment. Mutations responsible for the disease is usually inherited from earlier generations and therefore it is essential to trace the disease history of the family. Though it is not possible to revert the mutation in causing the disease, however changes in lifestyle and living environment can help to attenuate the effect of the disease. Some of the common diseases (multifactorial inheritance) due to inheritance are diabetes, cancer, heart disease, high blood pressure, Alzheimer’s disease, arthritis, and obesity etc.
3) Kessler C. (2018) Genomics and Precision Medicine: Implications for Critical Care. AACN Adv Crit Care.
Dr. Susanta Pahari, is a Professor in the Department of Biochemistry at Skyline University Nigeria. He has a PhD. in Biochemistry from the University of Calcutta, India.