Conserved SDH blocks in the six different lineages. “c”, a charged residue; “h”, a hydrophobic residue; “p”, a polar residue and “x”, any residue. Alternative amino acids at a given position are shown within brackets. Red background indicates strictly conserved amino acids, orange background indicates conserved amino acids and blue boxes indicate the specific blocks of each lineage. Guidance scores represent the degree of confidently aligned residues (1 corresponds to 100% certainty) [25, 26].