A cytological study in some of the Allium species in Iran

Cytological studies are performed to compare the differences between species and to reveal the evolutionary process of the chromosomes that construct the genome. The study of karyotype plays an important role in determining the relationship between species and can be considered as the first step in the analysis of the genealogy and evolution of species. In this study, the characteristics of karyotype and chromosome number of four endemic species of Iran from Allium including A. ubipetrense, A.zagricum, A. derderianum, and A. alamutense have been investigated. This study was based on mitotic observation of root tips meristem cells according to Agayev method. the chromosome length and the ratio of the arms were measured and symmetry indices such as DI, Syi, Rec, AI and indicators related to the diversity of centromere position such as TF%, AsK % and A were calculated. The results confirm the close relationship between the species and also indicate that there are approximately symmetric karyotypes containing metacentric and submetacentric chromosomes. The mitosis analysis showed that these species have a chromosome number of 2n=2x=16 and the basic chromosome number is x=8. Based on all indices, A. ubipetrense is the most symmetric and A. zagricum is the most asymmetric species. Regarding the high morphological and karyological similarities between species, it can be concluded that diversity in this group of species has recently been made and speciation is not accompanied with significant changes in chromosome number and structure but was probably connected with changes at the DNA level that are not reflected in chromosome structure.

Keywords:

Iran , Cytotaxonomy , Karyology , Allium