dhfr triple mutant He changes over time (51I/108N/164L).

The figure shows variation in He surrounding dhfr for parasites carrying the 51I/108N/164L mutant during the 1980s (n = 8) and 1990s (n = 19). He surrounding this allele appears to have increased between the two periods. The two flat, dashed lines represent two different estimates of neutral He in Brazil.