Abstract
In this study, the karyomorphology of 20 Turkish Centaurea (subgenus Cyanus) taxa was examined. The number of chromosomes of 11 taxa belonging to the subgenus Cyanus was determined for the first time. As a result of the karyomorphological studies, the number of basic chromosomes was determined to be x = 8, 10, and 12 in annuals and x = 10 and 11 in perennials. The populations are tetraploid in the seven perennial taxa and polyploidy is not rare for this group. On the other hand, all annual taxa are diploid. Considering the asymmetry indices, we can conclude that most taxa have symmetrical karyotypes. The most common karyotype formulas are 40 metacentric chromosomes (m), 20m, and 16m + 4 submetacentric chromosomes, respectively. A satellite was detected in the majority of the taxa, but it was observed to be mainly localized on the short arm of the chromosome. Satellites are located mainly on the second chromosome.
Highlights
Cytotaxonomy is a branch of cytogenetics in which karyological features are systematically evaluated for evolutionary purposes (Siljak-Yakovlev and Peruzzi, 2012)
Because the genetic information of an organism is transmitted through its chromosomes, any changes in numbers and structures contribute significantly to plant evolution and speciation; to interpret the evolutionary history of a group, the number of chromosomes alone is not enough (Weiss-Schneeweiss and Schneeweiss, 2003) and karyomorphology might supply additional information
Ecological and morphological data might not be sufficient for analyzing the line of descent among the species
Summary
Cytotaxonomy is a branch of cytogenetics in which karyological features are systematically evaluated for evolutionary purposes (Siljak-Yakovlev and Peruzzi, 2012). Chromosomes, especially plant chromosomes, are useful materials in nearly any type of cytogenetic research (Guerra, 2012). Because the genetic information of an organism is transmitted through its chromosomes, any changes in numbers (e.g., polyploid or diploid) and structures (e.g., inversion, deletion, or translocation) contribute significantly to plant evolution and speciation; to interpret the evolutionary history of a group, the number of chromosomes alone is not enough (Weiss-Schneeweiss and Schneeweiss, 2003) and karyomorphology might supply additional information. Ecological and morphological data might not be sufficient for analyzing the line of descent among the species. In these situations, cytotaxonomic relationships along with molecular data might be more influential in the analyses (Venora et al, 2008). The karyotype reveals phenotypic appearance in terms of number, size, arm ratio, centromere position, and other basic characteristics of chromosomes (Levin, 2002)
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