Contrasted microcolinearity and gene evolution within a homoeologous region of wheat and barley species.
We study here the evolution of genes located in the same physical locus using the recently sequenced Ha locus in seven wheat genomes in diploid, tetraploid, and hexaploid species and compared them with barley and rice orthologous regions. We investigated both the conservation of microcolinearity and the molecular evolution of genes, including coding and noncoding sequences. Microcolinearity is restricted to two groups of genes (Unknown gene-2, VAMP, BGGP, Gsp-1, and Unknown gene-8 surrounded by several copies of ATPase), almost conserved in rice and barley, but in a different relative position. Highly conserved genes between wheat and rice run along with genes harboring different copy numbers and highly variable sequences between close wheat genomes. The coding sequence evolution appeared to be submitted to heterogeneous selective pressure and intronic sequences analysis revealed that the molecular clock hypothesis is violated in most cases.
Chantret
Nathalie
N
Domaine de Melgueil, INRA-UMR DIAPC, 34130 Mauguio, France. chantret@supagro.inra.fr
Salse
Jérôme
J
Sabot
François
F
Bellec
Arnaud
A
Laubin
Bastien
B
Dubois
Ivan
I
Dossat
Carole
C
Sourdille
Pierre
P
Joudrier
Philippe
P
Gautier
Marie-Françoise
MF
Cattolico
Laurence
L
Beckert
Michel
M
Aubourg
Sébastien
S
Weissenbach
Jean
J
Caboche
Michel
M
Leroy
Philippe
P
Bernard
Michel
M
Chalhoub
Boulos
B
D001483:Base Sequence; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D032461:Chromosomes, Plant / Q000235:genetics; D003062:Codon / Q000235:genetics; D017124:Conserved Sequence; D021901:DNA, Intergenic / Q000235:genetics; D019143:Evolution, Molecular; D017343:Genes, Plant / Q000235:genetics*; D001467:Hordeum / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics; D014908:Triticum / Q000235:genetics*
D003062:Codon; D021901:DNA, Intergenic