BLAST

Protein BLAST (blastp) is used to analyze the protein sequences of the MARK2 homologues in 5 species – Homo sapiens, Mus musculus, Xenopus laevis, Rattus norvegicus and Bos taurus. BLAST stands for Basic Local Alignment Search Tool [1]. Protein BLAST searches protein database using a protein query for regions of local similarity between protein sequences and calculates the statistical significance of matches [1].

Protein BLAST gives the maximum score, total score, query coverage, E value and identity. The score is the normalized score of alignment that can be compared across searches [2]. The maximum score is the score of single best aligned sequence, while the total score is the sum of scores of all aligned sequences [2]. Query coverage is the percentage of query sequence that is aligned [2]. The E value is the number of alignments with scores that are equal to or better than the threshold value that is expected to occur in a database search by chance [3]. As the E value decreases, the score and the alignment become more significant [3]. Typically, an E value of smaller than 0.05 is considered significant [2]. Identity is the percentage of sequence identity.

The results of the BLAST search for the five different species are presented below. They are selected based on high query coverage (96% or more) and high percentage of sequence identity (80% or more)