Reference "Numerous small rearrangements of gene content, order and orientation differentiate grass genomes"

Reference ID

6834

Title

Numerous small rearrangements of gene content, order and orientation differentiate grass genomes

Source

Plant molecular biology, 2002, vol. 48, pp. 821-827

Authors (2)

Bennetzen-J-L

Ramakrishna-W

Abstract

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.