Neurogenetics and Neurogenomics
Neurogenetics and neurogenomics are described together in this chapter. The term “neurogenomics” is a distinct term from “neurogenetics” in the same way as the parent terms of genomics and genetics, but they are described together in this chapter. Genetics plays an important role in almost every disease. The total genetic material of an organism, that is, an organism’s complete DNA sequence is called a genome. A gene is defined as a DNA segment that contributes to phenotype/function. In the absence of demonstrated function a gene may be characterized by sequence, transcription or homology. The current estimate of genes in the human genome is 20,000–25,000. For practical purposes, a gene is a physical and functional unit of heredity, which carries information from one generation to the next. In molecular terms, it is the entire DNA sequence including exons, introns, and noncoding transcription control regions that are necessary for production of a functional protein or RNA. The genome products − transcriptomes and proteomes − vary in time and space. The genetic information in DNA is not directly converted into proteins, but must first be copied, i.e. transcribed into RNA. Whereas genetics is the study of single genes and their effects, genomics is the study not only of single genes, but also of the functions and interactions of all the genes in the genome. Neuroproteomics will be described in the following chapter.