ARS | Publication request: Major Cytogenetic Landmarks and Karyotype Analysis in Carrot (Daucus carota L.) and Other Apiaceace

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 3, 2008
Publication Date: January 10, 2008
Citation: Iovene, M., Grzebelus, E., Carputo, D., Jiang, J., Simon, P.W. 2008. Major Cytogenetic Landmarks and Karyotype Analysis in Carrot (Daucus carota L.) and Other Apiaceace [abstract]. 2008 Plant and Animal Genome Meeting. p. 201.

Technical Abstract: Karyotyping can be helpful for understanding species evolution and relationships. Cytological studies in Apiaceae have provided information on the chromosome number and morphology of several crops. However, karyological data of their wild relatives are scarce. In addition, the number of chromosomes bearing the NOR is controversial. This study was undertaken to investigate the distribution of rDNA loci in 21 species among cultivated and wild Apioideae using FISH. Interestingly, Daucus species with diverse chromosome numbers (2n=18, 20, 22 and 44) did not vary for the number of the rDNA sites. However, the 5S rDNA was on the short arm of a metacentric chromosome pair in D. crinitus (2n=22) and D. glochidiatus (2n=44), and on the long arm of a metacentric pair in the other Daucus. This suggested a possible chromosomal rearrangement within the genus. The other species included anise, celery, coriander, cumin, fennel, parsley and pastinaca, and varied for number and position of the rDNA sites. Chromosome length and arm ratio allowed classifying the chromosomes in two to four groups, without any further identification possible beyond the FISH signals. To generate additional chromosome landmarks, map-anchored carrot BAC clones are being probed on the chromosomes of several Daucus species. A BAC clone anchored to the linkage group 6 (Just et al., 2007) enabled us to locate the 18S-25S rDNA in carrot. This ongoing work will create the foundation for the integration of genetic and physical maps in D. carota and will possibly shed light on the karyotype evolution in the Daucus genus.