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 [...]
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. [...]
In this article we will discuss about the gene action in drosophila. Beadle and Ephrussi (1937) studied metabolic pathway for eye colour in Drosophila. There are three eye colours in the fruitfly, viz. wild, vermillion and cinnabar. Procedure: The imagine disc or primordia was transplanted from one larva on to the abdomen of other larva. Reciprocal eye transplantation was made [...]