Introduction to Medical Genetics

Medical genetics involves the application of genetics for the diagnosis and management of hereditary disorders. With the advancement of medical technology, the scope of medical genetics has widened to include the gene interactions, control of gene expressions, gene variations, and environmental interactions. Genetic diseases are now categorized as classical and non-classical. Classical diseases include the chromosomal disorders, Mendelian disorders, and multifactorial disorders. In the non-classical genetic diseases, there is a single gene disorder with an atypical pattern of inheritance. They include the diseases caused by mutations in mitochondrial genes, triplet repeat mutations, genomic imprinting, gonadal mosaicism, and uniparental disomy. Medical genetics differ from human genetics in that human genetics is a field of scientific research that, or may not, apply to medicine, while medical genetics refers to the application of genetics to medical care.

Monoallelic gene expression refers to the allele-specific expression of genes. Only one allele of the gene is actively transcribed. It can occur in different ways, such as genomic imprinting, random choice of one allele, and X-inactivation. Other allele expressions are balanced and unbalanced expressions. Balanced expressions have both alleles equally expressed, whereas unbalanced ones do not express each allele equally. Goldilocks principle states that everything should fit in a certain margin; neither too much nor too less. When the amount of gene product changes, it no longer follows the “just right” principle of Goldilocks.

Genomics is the study of what the genome does. In this article, we include the topics of distinguishing between genetic and physical maps, describing the process of DNA sequencing and characterizing two different methods for sequencing genomes— the clone-by-clone vs. shotgun sequencing.

Chromosomal aberrations are chromosome mutations which entail changes in the genome. These changes can affect either parts of a chromosome, or an entire chromosome.The change in genetic material can be due to loss, gain of extra genetic material or rearrangement of the existing genetic material. These aberrations are the source of genetic mutations. Chromosomal aberrations can be even further categorized into numerical and structural chromosomal aberrations.

There is a variety of applications that can be done using recombinant DNA technology. This is why it important to develop libraries for the genomes of organisms so that it will be easier for scientist to isolate desired genes of interest. This topic review discusses DNA libraries and how they are developed. Also given in this article are the applications of biotechnology in the field of forensics, medicine and agriculture. Blotting techniques and how they apply in forensic investigation are included in this article as well.

Biotechnology is the use of biological organisms or processes to develop products or improve the quality of life. One common technology studied is the Recombinant DNA technology. DNA of two organisms are combined to improve characteristics and properties of an organism. Modification of the DNA also is done to develop new pharmaceutical therapies and diagnostic tests. In this article different techniques in biotechnology are discussed, namely, recombinant DNA technology, Polymerase Chain Reaction, Gel Electrophoresis and CRISPR Cas9.

Transcription and translation convert a gene into protein. During this process, the genetic information of a gene, the DNA, is converted into RNA so that protein may be realized later on. This article will provide you with exam-related information regarding this process, thus preparing you ideally for the upcoming exams.

Mutations are associated with diseases and defective genes. Mutated genes are actually the cause of many diseases, although they are also necessary. Without permanent change in the genome, evolution is not possible, and purely static DNA would prevent any development. DNA is also the only molecule of the cell that is repaired. The information stored in the DNA is so important that the energy expended by repairing it is worthwhile. The cell must find the correct balance between the loss of evolution by mutation, and evolution by mutation.

In the medical field, the topic of Genetics is of significant importance. The topic explains how an organism is able to pass on its characteristics to its offspring. In this article, you will be able to learn about the structure and function of the human gene. Processes such as replication, transcription and translation are also explained in detail to help you get the required insight on what happens in each process. Furthermore, there are a few questions at the end of the article that will help you to test your understanding. You will find the answers to these questions below the references.