example_1:
%
>gene_A_homo.sapiens
ATGGCTGAAAGTGGAAAAGAAAAAATAAAATGGACAACCACCATT
>gene_A_canis.familiaris
ATGGCTGAAAATGGCAGAAAAGAAAAAGTAAAATGGACAACCACC
Here: number of sets of orthologuous genes = 1 (gene_A)
and number of species = 2 (homo_sapiens, canis_familiaris)
example_2:
%
>gene1_homo.sapiens
ATGCCTTTTCAATTTGGAACCCAGCCAAGGAGGTTTCCAGTGGAAGGAGGAGATTCTTCAATTGAGCTGGAA
>gene1_mus_musculus
ATGCCTTTTCGGTTTGGGACCCAGCCAAGGAGGTTTCCAGTGGAAGGAGGAGATTCTTCAATTGGGCTAGAA
>gene1_canis.familiaris
ATGCCTTTTCGGTTTGGGACCCAGCCAAGGAGGTTTCCAGTGGAAGGAGGAGACTCTTCAATTGAGCTAGAA
%
>gene2_homo.sapiens
ATGGCTGAAAGTGGAAAAGAAAAAATAAAATGGACAACCACCATT
>gene2_mus.musculus
ATGGCTGAAAATGGCAGAAAAGAAAAAGTAAAATGGACAACCACC
>gene2_canis.familiaris
ATGGCTGAAAATGGCAGAAAAGAAAACAGTAAAATGGACAACCACC
%
>gene3_homo.sapiens
ATGACCCAGCCAAGGAGGTTTCGTTTCCAGTGGAAGGAGGAGATTCTTCAACAG
>gene3_canis_familiaris
ATGACCCAGCCAAGGAGGTTTCTTTTCCAGTGGAAGGAGGAGATTCTACAACAG
>gene3_mus_musculus
>ATGACCCAGCCAAGGAGGTTTATTTCCAGTGGAAGGAGGAGATCCTTCAACAG
%
>gene4_homo.sapiens
ATGCCTTTTCAATTTGGAACCCAGCCAAGGAGGTTTCCAGTGGAAGGAGGAGATTCTTCAATTGAGCTGGAT
>gene4_mus_musculus
ATGCCTTTTCGGTTTGGGACCCAGCCAAGGAGGTTTCCAGTGGAAGGAGGAGATTCTTCAATTGGGCTAGAT
>gene4_canis.familiaris
ATGCCTTTTCGGTTTGGGACCCAGCCAAGGAGGTTTCCAGTGGAAGGAGGAGACTCTTCAATAGAGCTAGAT
Here : number of sets of orthologuous genes = 4 (gene1, gene2, gene3, gene4)
and number of species = 3 (homo_sapiens, mus_musculus, canis_familiaris)