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Comprehensive molecular cytogenetic analysis of sorghum genome architecture: distribution of euchromatin, heterochromatin, genes and recombination in comparison to rice

Informally Refereed

Abstract

Cyteogenetic maps of sorghum chromosomes 3-7, 9, and 10 were constructed on the basis of the fluorescence in situ hybridization (FISH) of ~18-30 BAC probes mapped across each of these chromosomes. Distal regions of euchromatin and pericentromeric regions of heterchromatin were delimited for all 10 sorghum chromosomes and their DNA content quantified. Euchromatic DNA spans ~50% of the sorghum genome, ranging from ~60% of chromosome 1 (SBI-01) to ~33% of chromosome 7 (SBI-07. This portion of the sorghum genome is predicted to encode ~70% of the sorghum genes (~1 gene model/12.3 KBP), assuming that rice and sorghum encode a similar number of genes. Heterchromatin spans ~411 Mbp of the sorghum genome, a region characterized by a ~34-fold lower rate of recombination and a ~3-fold lower gene density compared to euchromatic DNA. sorghum and rice genomes exhibit a high degree of macrocolineaity; however, the sorghum genome is ~2-fold larger than the rice genome. The distal euchromatic regions of sorghum chromosomes 3-7 and 10 are ~1.8-fold larger overall and exhibit an ~1.5-fold lower average rate of recombination than the colinear regions of the homeologous rice chromosomes. By contrast, the pericentromeric heterochromatic regions of these chromosomes are on average ~3.6-fold larger in sorghum and recombination is suppressed ~15-fold compared to the colinear regions of rice chromosomes.

Citation

Kim, J.-S; Islam-Faridi, M.N.; Klein, P.E.; Stelly, D.M.; Price, H.J.; Klein, R.R.; Mullet, J.E. 2005. Comprehensive molecular cytogenetic analysis of sorghum genome architecture: distribution of euchromatin, heterochromatin, genes and recombination in comparison to rice. Genetics, Vol. 171: 1963-1976
Citations
https://www.fs.usda.gov/research/treesearch/25215