Microcolinearity in sh2-homologous regions of the maize, rice, and sorghum genomes

作者：Chen M; SanMiguel P; deOliveira AC; Woo SS; Zhang H; Wing RA; Bennetzen JL

来源：Proceedings of the National Academy of Sciences, 1997, 94(7): 3431-3435.

DOI：10.1073/pnas.94.7.3431

• genome microsynteny
• gene duplication
• repetitive DNA
• intron evolution

Large regions of genomic colinearity have been demonstrated among grass species by recombinational mapping, but the degree of chromosomal conservation at the sub-centimorgan level has not been extensively investigated, We cloned the rice and sorghum genes homologous to the sh2 locus of maize on bacterial artificial chromosomes (BACs), and observed that a homologue of the maize al gene was also present on each of these BACs, In sorghum, we found a direct duplication of al homologues separated by about 10 kb, In maize, sh2 and al are approximately 140 kb apart and transcribed in the same direction, with sh2 upstream of al, In rice and sorghum, this arrangement is fully conserved, However, the sh2 and al homologues are separated by about 19 kb in both rice and sorghum, We found low-copy-number and repetitive DNAs between the sh2 and al homologues of sorghum and rice, The sh2 and al homologues cross-hybridized, but the repetitive DNA and most low-copy-number sequences between these genes did not, These results indicate that maize, sorghum, and rice have conserved gene order and composition in the sh2-a1 region, but have acquired extensive qualitative and quantitative differences in the sequences between these genes.

• 出版日期1997-4-1