CSB325H1 Lecture Notes - Lecture 7: Chondrichthyes, Urocortin, Acanthopterygii
18 Dec 2013
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Document Summary
All key hormones associated with digestion utilize gpcr, with the exception of insulin which uses a kinase receptor system. In digestive endocrinology, a number of peptides are structurally related and are therefore grouped in families. The degree of relatedness indicates an evolutionary relationship among these families. Similar hormones may be utilized by a variety of species to carry out similar functions. However, these hormones and their genes may vary in structure due to changes that occur during evolution. Orthologues gene (hormone) changes as a function of species divergence. Consequently, hormones and their genes are classified as homologues, orthologues, or paralogues. The number of hormones in an organism is directly related to the amount of genetic material present. An increase in the genetic complexity is determined by the number of gene and genomic duplications. Early vertebrates appear to have two major genome duplication events. Later genomic duplication events occurred in cartilaginous fish, amphibians and ray finned fishes.
