In the G. tsugae genome, genes related to fanconi anemia pathway, homologous recombination, and mismatch repair were expanded and positively selected, such as bloom syndrome protein (blm), DNA mismatch repair protein (mlh1), replication factor C subunit 1 (rfc1), DNA polymerase delta subunit 1 (pold1), fanconi-associated nuclease 1 (fan1), and DNA excision repair protein (ercc1). The gene discussed is POLD1; the disease is Fanconi anemia.