Sequence analysis and molecular evolutionary assessment of Eucalyptus spp. across different environmental regions within Baghdad city based on the complete ITS region of nuclear ribosomal DNA.

• Thaer Hamid A. Hajeej

  Author

To explore the genetic diversity and molecular evolution of Eucalyptus spp., 20 reference ITS sequences from various areas were analysed. The GC content varies from 60.51% to 64.07%, with an average of 61.99%. The data revealed that transition substitutions were more common than transversions in the ITS region, with an overall transition/transversion bias (R) of 2.229. Eighteen different haplotypes were found after analysing the 20 Eucalyptus species DNA. The aligned ITS dataset includes 56 polymorphic sites, which included 25 singleton variable sites and 31 parsimony-informative sites. A non-geographically structured clustering pattern was identified among the overall Eucalyptus spp. reference sequences in the Neighbor-Joining (NJ) phylogenetic tree, indicating a lack of grouping according to geographic basis. The E. erythrocorys (YRM) accession had the highest degree of genetic divergence, with a genetic distance of 10.250, as confirmed by both principal component analysis (PCA) and haplotype network analysis. The first three principal components accounted for 70.748% of the overall genetic variation, showing a significant amount of the dataset's genetic structure. Furthermore, molecular evolutionary and neutrality test results demonstrate that the whole dataset supports a neutral evolutionary model in Eucalyptus communities, with no significant divergence from neutrality or evidence of recent demographic expansion.

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