The Sorghum bicolor genome and the diversification
of grasses
Andrew H. Paterson1,
John E. Bowers1,
Rémy Bruggmann2,
Inna Dubchak3,
Jane Grimwood4,
Heidrun Gundlach5,
Georg Haberer5,
Uffe Hellsten3,
Therese Mitros6,
Alexander Poliakov3,
Jeremy Schmutz4,
Manuel Spannagl5,
Haibao Tang1,
Xiyin Wang1,7,
Thomas Wicker8,
Arvind K. Bharti2,
Jarrod Chapman3,
F. Alex Feltus1,9,
Udo Gowik10,
Igor V. Grigoriev3,
Eric Lyons11,
Christopher A. Maher12,
Mihaela Martis5,
Apurva Narechania12,
Robert P. Otillar3,
Bryan W. Penning13,
Asaf A. Salamov3,
Yu Wang5,
Lifang Zhang12,
Nicholas C. Carpita14,
Michael Freeling11,
Alan R. Gingle1,
C. Thomas Hash15,
Beat Keller8,
Patricia Klein16,
Stephen Kresovich17,
Maureen C. McCann13,
Ray Ming18,
Daniel G. Peterson1,19,
Mehboob-ur-Rahman1,20,
Doreen Ware12,21,
Peter Westhoff10,
Klaus F. X. Mayer5,
Joachim Messing2
& Daniel S. Rokhsar3,4
Sorghum, an African grass related to sugar cane and maize, is grown for
food, feed, fibre and fuel. We present an initial analysis of the 
730-megabase
Sorghum bicolor (L.) Moench genome, placing 98%
of genes in their chromosomal context using whole-genome shotgun
sequence validated by genetic, physical and syntenic information.
Genetic recombination is largely confined to about one-third of the
sorghum genome with gene order and density similar to those of rice.
Retrotransposon accumulation in recombinationally recalcitrant
heterochromatin explains the 75%
larger genome size of sorghum compared with rice. Although gene and
repetitive DNA distributions have been preserved since
palaeopolyploidization 70
million years ago, most duplicated gene sets lost one member before the
sorghum–rice divergence. Concerted evolution makes one duplicated
chromosomal segment appear to be only a few million years old. About
24% of genes are grass-specific and 7% are sorghum-specific. Recent
gene and microRNA duplications may contribute to sorghum's drought
tolerance.