Figure 1From: Evidence of recombination among early-vaccination era measles virus strainsPhylogenetic trees reconstructed using the HKY substitution model and the minimum evolution criterion as implemented in MEGA 2.1 [25]. Bootstrap values >80% are shown. a) Tree based on the global post-vaccination era sample with classification of types marked, b) the same sequences as in a) plus the 18 early-vaccination era sequences, marked with a red circle.Back to article page