Gene dispersal

Armengaud J, B Happe, KN Timmis (1998) Genetic analysis of dioxin dioxygenase of Sphingomonas sp. strain RWl catabolic genes dispersed on the genome. J Bacterial 180 3954-3966. 

Unique sequences (genes), dispersed repeats, and multiple replication origins... 

More than 16 different types of collagen have been reported. They constitute the most abundant family of proteins in the human body. The collagens are encoded by 28 genes dispersed in at least 12 different chromosomes. 

Adams, W.T. 1992. Gene dispersal within forest tree populations. New For. 6 217-240. 

The results of the latter investigations, together with data from other systems, form the basis for the last part of this article, which speculates on the origin and evolution of eukaryotism and mechanisms of gene dispersal within eukaryotic cells. 

Intracellular Gene Dispersal Genes for Chlamydomonas Chloroplast Ribosomal Proteins... 

Other, less direct evidence, comes from the Chlamydomonas plastid-membrane cases discussed by Ohad (see Chapter 9) and the synthesis of yeast mitochondrial ATPase and cytochrome oxidase (see Chapters 1 and 5). If we assume that proteins made on plastid or mitochondrial ribosomes are coded for by organellar DNA and that those made on cytoplasmic ribosomes are coded for by nuclear genes, the number of cases of gene dispersal is greatly increased. 

Mechanisms of Gene Dispersal within Eukaryotic Ceils... 

First, what are some possible devices for intracellular gene dispersal And, secondly, what kinds of limits are imposed on the dispersal process why aren t all the genes for the organelle s ribosomes in the nuclear genome ... 

Fig. 19. A diagrammatic representation of the gene transfer mechanism of gene dispersal. Two steps are shown (a) A gene migration from the chloroplast to the nuclear genome, and (b) loss of the genes from the plastids. The result is the transfer of a sole site of genetic information for one of the ribosomal proteins from the plastid to the nuclear genome.

Fig. 20. A schematic diagram of the protein and gene substitution mechanisms of gene dispersal. The steps in the process are indicated in order. It is assumed in this diagram that a cytoplasmic ribosomai protein substitutes for the lost chloroplast ribosomai protein. This is shown here only for convenience.

This simplistic approach to cataloging the possible mechanisms of gene-dispersal and gene-product lock-in mechanisms is intended to help stimulate experiments to look for general principles of organelle biology or to deduce them from present knowledge. 

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