Phylogenetic Tree Analysis In this study, it was checked whether there is an evolutionary relationship between the available RNA nucleotide sequences Gr1 and Gr2, issued by the supervisor, and the prepared beforehand 16S rRNA gene sequence. It is essential to note in advance that the 16s rRNA nucleotide sequence of the gene was obtained using the open Nucleotide database owned by the National Centre for Biotechnology Information (NCBI), which allows finding the necessary sequence of the complete genome of the desired genus. The phylogenetic tree shown in Figure 1 was constructed using MEGA X software and based on the comparison of nucleotide sequences coding 16S rRNA. The analysis of this tree demonstrates that there is a direct genetic relationship between the analyzed Gr1 sample and the Rhodococcus genus. In particular, the sequence of Gr1 is as close as possible to the sequence of Rhodococcus degradans strain CCM 4446 , which is in the same clade with it. Moreover, Gr1 is still similar to all other strains in branches, but smaller with each new node and root. Given that, Gr1 was most likely isolated from an unknown organism at Newcastle, it can be argued that this organism was very close in evolution to Rhodococcus degradans strain CCM 4446 . Furthermore, given the research carried out by Švec et al . (2015), it can be assumed that this specimen is a previously undescribed species. At the same time, the Gr2 nucleotide sequence did not show any similarities and possibilities of gene alignment with the Rhodococcus genus. Fig. 1. The phylogenetic tree for Gr1 and Rhodococcus genus based on comparison of 16S rRNA gene (created by the author). Genome Size Analysis In-depth biological research of nucleotide sequences is not limited to the construction of the phylogenetic tree and requires analysis of the size of the genome. First of all, it is essential to clarify that the genome in this course work is understood as the number of base pairs that make up DNA (Paten et al ., 2017). At the same time, it is crucial to take into account that the full size of the prokaryotic genome includes not only the main DNA chain called the nucleoid, but also nucleotide sequences enclosed in plasmids and embedded bacteriophages (Raes et al ., 2007). No direct correlation between the size of the genome and the degree of development of the organism was found (Sela, Wolf and Koonin, 2016). Nevertheless, by comparing the genome size or weight of two potentially close strains of bacteria, geneticists may conclude that the species is relatively related or that the processes occurring within them are similar. For ease of analysis of Gr1 genome size and some species found using the phylogenetic tree, the genome size was measured in megabase. Fig. 2 shows quantitative similarities found between Gr1 and Rhodococcus qingshengii JCM 15477 . However, Fig. 1 confirms the phylogenetic similarity between the two organisms under study. Fig. 2. The comparison of genome sizes in megabase (created by the author). CG Content Analysis The GC-content analysis allows answering several critical questions concerning prokaryotes’ stability and their evolutionary proximity. It is known that DNA consists of f