Analyses of synteny between Arabidopsis thaliana and species in the Asteraceae reveal a complex network of small syntenic segments and major chromosomal rearrangements.
Comparative genomic studies among highly divergent species have been problematic because reduced gene similarities make orthologous gene pairs difficult to identify and because colinearity is expected to be low with greater time since divergence from the last common ancestor. Nevertheless, synteny between divergent taxa in several lineages has been detected over short chromosomal segments. We have examined the level of synteny between the model species Arabidopsis thaliana and species in the Compositae, one of the largest and most diverse plant families. While macrosyntenic patterns covering large segments of the chromosomes are not evident, significant levels of local synteny are detected at a fine scale covering segments of 1-Mb regions of A. thaliana and regions of <5 cM in lettuce and sunflower. These syntenic patches are often not colinear, however, and form a network of regions that have likely evolved by duplications followed by differential gene loss.
Timms
Lee
L
Biology Department, University of Massachusetts, Boston 02125, USA.
Jimenez
Rosmery
R
Chase
Mike
M
Lavelle
Dean
D
McHale
Leah
L
Kozik
Alexander
A
Lai
Zhao
Z
Heesacker
Adam
A
Knapp
Steven
S
Rieseberg
Loren
L
Michelmore
Richard
R
Kesseli
Rick
R
D017360:Arabidopsis / Q000235:genetics*; D002874:Chromosome Mapping / Q000379:methods; D032461:Chromosomes, Plant / Q000235:genetics*; D006368:Helianthus / Q000235:genetics*; D018545:Lactuca / Q000235:genetics*