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GrainGenes Reference Report: PMB-48-821

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Reference	PMB-48-821
Title	Numerous small rearrangements of gene content, order and orientation differentiate grass genomes
Journal	Plant Molecular Biology
Year	2002
Volume	48
Pages	821-827
Author	Bennetzen JL Ramakrishna W
Abstract	Summary: Comparative genetic mapping has indicated that the grass family (Poaceae) exhibits extensive chromosomal collinearity. In order to investigate microcollinearity in these genomes, several laboratories have begun to undertake comparative DNA sequence analyses of orthologous chromosome segments from various grass species. Five different regions have now been investigated in detail, with four regions sequenced for maize, rice and sorghum, plus two for wheat and one for barley. In all five of these segments, gene rearrangements were observed in at least one of the comparisons. Most of the detected rearrangements are small, involving the inversion, duplication, translocation or deletion of DNA segments that contain only 1-3 genes. Even closely related species, like barley and wheat or maize and sorghum, exhibit approximately 20% alterations in gene content or orientation. These results indicate that thousands of small genetic rearrangements have occurred in several grass lineages since their divergence from common ancestors. These rearrangements have largely been missed by genetic mapping and will both complicate and enrich the use of comparative genetics in the grasses
Keyword	[ Hide all but 1 of 39 ] arabidopsis thaliana barley brassica chromosome chromosome segments collinearity comparative genetic mapping comparative genetics conservation deletion divergence dna dna sequence duplication family gene genetic mapping genome genomic sequencing grass genomes intergenic regions inversion maize mapping mutation order organization orientation poaceae rearrangements region rice segment sequence sequence analyses sequence data sorghum synteny translocation

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