Maximum Likelihood phylogenetic tree. The tree was generated using 44 nucleotide sequences of the HPV L1 gene. Six allele clusters comprised of HPV 6, HPV 11, HPV 16, HPV 18, HPV 31 and HPV 81 genotypes. NCBI accession numbers are listed with sample number. Reference sequences include HPV 6 (GU344803.1), HPV 11 (GU344763.1), HPV 16 (FJ797753.1), HPV 18 (GU344774.1), HPV 31 (HM596539.1) and HPV 81 (GQ288793.1). The outgroup sequence is the human HPV 2 (JN415125.1).