The organization and rate of evolution of wheat genomes are correlated with recombination rates along chromosome arms.
Genes detected by wheat expressed sequence tags (ESTs) were mapped into chromosome bins delineated by breakpoints of 159 overlapping deletions. These data were used to assess the organizational and evolutionary aspects of wheat genomes. Relative gene density and recombination rate increased with the relative distance of a bin from the centromere. Single-gene loci present once in the wheat genomes were found predominantly in the proximal, low-recombination regions, while multigene loci tended to be more frequent in distal, high-recombination regions. One-quarter of all gene motifs within wheat genomes were represented by two or more duplicated loci (paralogous sets). For 40 such sets, ancestral loci and loci derived from them by duplication were identified. Loci derived by duplication were most frequently located in distal, high-recombination chromosome regions whereas ancestral loci were most frequently located proximal to them. It is suggested that recombination has played a central role in the evolution of wheat genome structure and that gradients of recombination rates along chromosome arms promote more rapid rates of genome evolution in distal, high-recombination regions than in proximal, low-recombination regions.
Akhunov
Eduard D
ED
Department of Agronomy and Range Science, University of California, Davis, California 95616, USA.
Goodyear
Andrew W
AW
Geng
Shu
S
Qi
Li-Li
LL
Echalier
Benjamin
B
Gill
Bikram S
BS
Miftahudin
Gustafson
J Perry
JP
Lazo
Gerard
G
Chao
Shiaoman
S
Anderson
Olin D
OD
Linkiewicz
Anna M
AM
Dubcovsky
Jorge
J
La Rota
Mauricio
M
Sorrells
Mark E
ME
Zhang
Deshui
D
Nguyen
Henry T
HT
Kalavacharla
Venugopal
V
Hossain
Khwaja
K
Kianian
Shahryar F
SF
Peng
Junhua
J
Lapitan
Nora L V
NL
Gonzalez-Hernandez
Jose L
JL
Anderson
James A
JA
Choi
Dong-Woog
DW
Close
Timothy J
TJ
Dilbirligi
Muharrem
M
Gill
Kulvinder S
KS
Walker-Simmons
M Kay
MK
Steber
Camille
C
McGuire
Patrick E
PE
Qualset
Calvin O
CO
Dvorak
Jan
J
D002874:Chromosome Mapping / Q000379:methods / Q000706:statistics & numerical data; D032461:Chromosomes, Plant / Q000235:genetics*; D019143:Evolution, Molecular; D020131:Genes, Duplicate / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D018745:Genome, Plant; D005810:Multigene Family / Q000235:genetics; D012275:Oryza / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014908:Triticum / Q000235:genetics*
D005819:Genetic Markers