The following points highlight the five major types of diseases of gene action in man. The types are: 1. Phenylketonuria 2. Alkaptonuria 3. Albinism 4. Tyrosinosis 5. Goitrous Cretinism. Disease of Gene Action in Man: Type # 1. Phenylketonuria: (i) Symptoms: This disease is characterized by high level of phenylalanine in blood, spinal fluid and sweat. High level of phenylalnine [...]
Notes on Biochemical Genetics: 1. Gene Action 2. Metabolic Pathway 3. Metabolic Disorders 4. Genetic Control 5. Organisms Studied. Biochemical Genetic: Point # 1. Gene Action: The manner in which genes control phenotypic expression of various characters in an organism is known as gene action. In other words, gene action refers to the functioning of genes (hereditary units) in determining [...]
In this article we will discuss about the gene action in bacteria. Tryptophan Biosynthesis in Salmonella: In Salmonella, tryptophan biosynthesis was studied by Brenner (1955). Tryptophan locus is mutable at four different sites. In other words, tryptophan synthesis consists of four biochemical steps. Reaction of each step is controlled by specific enzyme. Inactivation of an enzyme blocks a specific reaction. [...]