I am working with human mitochondrial genome and I used the MITOMASTER tool from mitomap to define haplogroups. Some sub-haplogroups appear with parentheses such as C1 (C1) while others appear alone "C1". I would like to know what is the difference between them and what the parentheses mean within the mtDNA haplogroup nomenclature. I couldn't find anything beyond the classic A B C nomenclature used to define the macro haplogroups. Thank you!