Naslov
Heterochromatin and rDNA organisation and evolution in the genus Reichardia

Autori
Šiljak-Yakovlev, Sonja ; Cerbah, Malika ; Zoldoš, Vlatka ; Godelle, B.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Cytogenetics and Cell Genetics / Olmo, Ettore - Basel : Karger Publishers, 1998

Skup
13th International Chromosome Conference

Mjesto i datum
Ancona, Italija, 08.09.1998. - 12.09.1998

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Sažetak
The Mediterranean genus Reichardia (Asteraceae) is a good model for investigation of genome organisation and evolution since it presents a little number of species (8-9, following authors) and three different basic chromosome numbers: x=7, 8, and 9. Two ancient-tertiary relic species from the Dinaric Alps and Anatolia refugiums (R. macrophylla and R. glauca) have x=9. The youngest and the only autogamous species R. picroides (circummediterranean geographic repartition) has a reduced basic chromosome number x=7. In this dysploid series (change of the basic chromosome number) other species, such as R. tingitan with large mediterranean repartition, neoendemic Iberian species R. gaditana, and three endemic species from Canary Islands, have an intermediate basic number x=8. Chromosomal and genomic evolution of this genus was studied through DNA content assessment, heterochromatin and rDNA organisation. To this end, molecular-cytogenetic methods (fluorochrome banding and fluorescent in situ hybridization FISH) and flow cytometry were applied. Chromosomal location of different types of constitutive heterochromatin, in respect of DNA base composition, was determined for each species. Chromomycin staining revealed GC rich heterochromatin always associated with nucleolar organizer regions (NORs) in the secondary constrictions (SC). Mapping of 18S-5.8S-26S and 5S rDNA by FISH was also realised. Genome size was well correlated with the basic chromosome number. The role of the heterochromatin in chromosomal restructurations during reduction of the chromosome nubmer and decrease of DNA content are discussed. One hypothetical schema of this evolutionary process is proposed. In addition, this study points out some evolutionary relationships between the species of the genus Reichardia.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA