ABSTRACT
Ideas about disease causation have a long and varied history and are still in flux today. Until recendy, gene-hunting methods required large pedigrees showing a clear Mendelian pattern of inheritance. A more complete rationalization is that multiple genetic and environmental factors all contribute to a disease liability. Human interest in heredity can be traced at least to the ancient Babylonians and Assyrians, who practiced artificial pollination as far back as 2000 bc, showing an awareness that traits could be passed from parents to offspring. He became the first Professor of Genetics in the world when he took the chair at Cambridge University. Modifier genes mean that traits that are inherited in a dominant fashion on one genetic background can be recessive or co-dominant on another, even when the environment is the same. Neurokines, also known as neuropoietins, are a small group of molecules which share structural similarities and employ common effector mechanisms in their target cells to cytokines.
