A computer-implemented method for determining if a nucleic acid sequence belongs to a microRNA (miRNA) candidate encoded by at least one known genomic sequence, comprising: a) determining if the nucleic acid sequence or the reverse complementary sequence thereof can fully align with a first subsequence of the known genomic sequence; b) then, - if the nucleic acid sequence fully aligns with the first subsequence of the known genomic sequence, determining if the reverse complementary sequence of the nucleic acid sequence can align with a second subsequence of the known genomic sequence with X error(s) at the most, or - if the reverse complementary nucleic acid sequence of the nucleic acid sequence fully aligns with the first subsequence of the known genomic sequence, determining if the nucleic acid sequence can align with a second subsequence of the known genomic sequence with X error(s) at the most; wherein X is an integer from 0 to 0.6L, wherein L is the length of the nucleic acid sequence, and a third subsequence of the known genomic sequence which consists of the first and second subsequences and of the portion of the known genomic sequence between the first and second subsequences has a length T, wherein T ≤ 3000 nucleotides; c) whereby, if conditions a) and b) are met, the nucleic acid sequence is determined to belong to a miRNA candidate. a) determining if the nucleic acid sequence or the reverse complementary sequence thereof can fully align with a first subsequence of the known genomic sequence; b) then, - if the nucleic acid sequence fully aligns with the first subsequence of the known genomic sequence, determining if the reverse complementary sequence of the nucleic acid sequence can align with a second subsequence of the known genomic sequence with X error(s) at the most, or - if the reverse complementary nucleic acid sequence of the nucleic acid sequence fully aligns with the first subsequence of the known genomic sequence, determining if the nucleic acid sequence can align with a second subsequence of the known genomic sequence with X error(s) at the most; wherein X is an integer from 0 to 0.6L, wherein L is the length of the nucleic acid sequence, and a third subsequence of the known genomic sequence which consists of the first and second subsequences and of the portion of the known genomic sequence between the first and second subsequences has a length T, wherein T ≤ 3000 nucleotides; - if the nucleic acid sequence fully aligns with the first subsequence of the known genomic sequence, determining if the reverse complementary sequence of the nucleic acid sequence can align with a second subsequence of the known genomic sequence with X error(s) at the most, or - if the reverse complementary nucleic acid sequence of the nucleic acid sequence fully aligns with the first subsequence of the known genomic sequence, determining if the nucleic acid sequence can align with a second subsequence of the known genomic sequence with X error(s) at the most; wherein X is an integer from 0 to 0.6L, wherein L is the length of the nucleic acid sequence, and a third subsequence of the known genomic sequence which consists of the first and second subsequences and of the portion of the known genomic sequence between the first and second subsequences has a length T, wherein T ≤ 3000 nucleotides; c) whereby, if conditions a) and b) are met, the nucleic acid sequence is determined to belong to a miRNA candidate.