Genetic mapping of expressed sequences in onion and in silico comparisons with rice show scant colinearity.
The Poales (which include the grasses) and Asparagales [which include onion (Allium cepa L.) and other Allium species] are the two most economically important monocot orders. Enormous genomic resources have been developed for the grasses; however, their applicability to other major monocot groups, such as the Asparagales, is unclear. Expressed sequence tags (ESTs) from onion that showed significant similarities (80% similarity over at least 70% of the sequence) to single positions in the rice genome were selected. One hundred new genetic markers developed from these ESTs were added to the intraspecific map derived from the BYG15-23xAC43 segregating family, producing 14 linkage groups encompassing 1,907 cM at LOD 4. Onion linkage groups were assigned to chromosomes using alien addition lines of Allium fistulosum L. carrying single onion chromosomes. Visual comparisons of genetic linkage in onion with physical linkage in rice revealed scant colinearity; however, short regions of colinearity could be identified. Our results demonstrate that the grasses may not be appropriate genomic models for other major monocot groups such as the Asparagales; this will make it necessary to develop genomic resources for these important plants.
Martin
William J
WJ
Agricultural Research Service, USDA, Department of Horticulture, University of Wisconsin, Madison, 53706, USA. mjhavey@wisc.edu
McCallum
John
J
Shigyo
Masayoshi
M
Jakse
Jernej
J
Kuhl
Joseph C
JC
Yamane
Naoko
N
Pither-Joyce
Meeghan
M
Gokce
Ali Fuat
AF
Sink
Kenneth C
KC
Town
Christopher D
CD
Havey
Michael J
MJ
D001483:Base Sequence; D002874:Chromosome Mapping; D020224:Expressed Sequence Tags; D008040:Genetic Linkage; D005819:Genetic Markers / Q000235:genetics; D008969:Molecular Sequence Data; D019697:Onions / Q000235:genetics*; D012275:Oryza / Q000235:genetics*; D017422:Sequence Analysis, DNA; D026801:Synteny / Q000235:genetics
D005819:Genetic Markers