الفهرس 
Introductionيوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
The comparison of protein sequences according to similarity is a fundamental aspect of today’s biomedical research. Similarity/dissimilarity analysis is a key way of understanding the biology of an organism by knowing the origin of the new genes/sequences. With the developments of sequencing technologies, a large number of DNA and protein sequences increase exponentially in the public databases. Famous sequences comparison methods are alignment based. They generally give excellent results when the sequences under study are closely related and they are time-consuming. Fasta, Blast and Clustalw are well known alignment based methods.Herein, three alignment free methods are suggested. The first and the second suggested methods produce new graphical representations with new related numerical characterization and descriptors of DNA and protein sequences. The graphical representation is a simple way to visualize biological sequences. The descriptor compresses the primary sequence into numerical values that easy to compare. The similarity/dissimilarity analysis is introduced in the form of a square matrix. The first approach is applied on both DNA and protein primary sequences. The second approach is applied on protein sequences. Our approach gives good results with both short and long sequences within a little computation time. The 1st approach is applied on 8 species of 1st exon of β- globin gene, 15 species of beta globin protein sequences and 9 species of ND5 (NADH dehydrogenase subunit 5) protein sequences. The 2nd approach is applied on nine beta globin, nine ND5 (NADH dehydrogenase subunit 5) and 24 spike protein sequences. Correlation and significance analyses are also introduced to compare and approve our similarity/dissimilarity results with others’ approaches, results and sequence homology.All the present alignment-free methods approve the utility of their approaches by producing a square imilarity/ dissimilarity matrix. Although, it is clear, it measures the degree of similarity among sequences individually. Our third approach is a new (non-graphical representation) alignment free method. The approach is applied on three selected groups of protein sequences: beta globin, NADH dehydrogenase subunit 5 (ND5), and spike protein sequences. A representative of each of three groups of protein sequences is introduced. A similarity/dissimilarity vector is evaluated instead of the ordinary similarity/dissimilarity matrix based on the group representative. A cross-grouping comparison is produced to ensure the singularity of each group. A qualitative comparison between our approach, previous articles, and the phylogenetic tree of these protein sequences proved the utility of our approach.