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    Chromosome diversity and evolution in Allium (Allioideae, Amaryllidaceae)
    (TAYLOR & FRANCIS LTD, 2017) Peruzzi, Lorenzo; Carta, Angelino; Altınordu, Fahim
    Despite extensive literature on the diversity of karyotypes in Allium is available, no attempt to analyse these data together, within a robust phylogenetic framework, has been carried out so far. Thus, we examined patterns and trends in chromosome evolution across the genus. Based on literature survey, karyo-morphometric features for 207 species belonging to 12 subgenera of Allium were obtained. Included in the data-set were basic chromosome number (x), somatic chromosome number (2n), total haploid (monoploid) chromosome length (THL) and three different measures defining karyotype structure: CVCI, measuring how heterogeneous are centromeres positions in a karyotype, CVCL and M-CA, quantifying interchromosomal and intrachromosomal karyotype asymmetry, respectively. Trends in karyotype evolution were analysed by phylogenetic regressions and independent contrasts. Mean karyotypes highlighted differences and similarities in karyotype structure between the 12 subgenera. Further differences were noted when the two parameters for analysing karyotype asymmetry were assessed. In addition, by examining the effects of increasing karyotype dimensions (a proxy for genome size) on karyotype structure and asymmetry, it was shown that in Allium species, the DNA was added proportionally to their arm lengths. Overall, p=8 and somehow intermediate karyotype asymmetry levels seem to represent plesiomorphic character-states in Allium.
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    A proposal for a multivariate quantitative approach to infer karyological relationships among taxa
    (PENSOFT PUBLISHERS, 2014) Peruzzi, Lorenzo; Altinordu, Fahim
    Until now, basic karyological parameters have been used in different ways by researchers to infer karyological relationships among organisms. In the present study, we propose a standardized approach to this aim, integrating six different, not redundant, parameters in a multivariate PCoA analysis. These parameters are chromosome number, basic chromosome number, total haploid chromosome length, MCA (Mean Centromeric Asymmetry), CVCL (Coefficient of Variation of Chromosome Length) and CVCI (Coefficient of Variation of Centromeric Index). The method is exemplified with the application to several plant taxa, and its significance and limits are discussed in the light of current phylogenetic knowledge of these groups.
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    A tool for the analysis of chromosomes: KaryoType
    (INT ASSOC PLANT TAXONOMY-IAPT, 2016) Altinordu, Fahim; Peruzzi, Lorenzo; Yu, Yan; He, Xingjin
    The software KaryoType, an improved and completely renewed version of the previously existing NucType, was developed for plant chromosomes. The primary function of the software is to allow efficient chromosome measurements and karyotype analysis from microphotographs. Karyotype characterization usually includes chromosome number, size, arm ratio, centromeric index, relative lengths and karyotype formula. Moreover, KaryoType is also capable of measuring karyotype asymmetry indices such as CVCL, CVCI and M-CA, and can recognize chromosome homologues based on chromosome length and arm ratio automatically or manually. This program runs on Windows 7 and above and Mac OS X and is freely available at the website of the University of Sichuan (http://mnh.scu.edu.cn/soft/blog/karyotype/).