The researchers haven't yet found the exact mutation responsible for the worm resistance and asthma susceptibility. (sciencemag.org)
In the case of β - ionone, the smell associated with violets, McRae and colleagues managed to pinpoint the exact mutation (a change in the DNA sequence) in the odorant receptor gene OR5A1 that underlies the sensitivity to smell the compound and to perceive it as a floral note — people who are less good at smelling β - ionone also describe the smell differently, as sour or pungent, and are less likely to find it pleasant. (sciencedaily.com)
But despite decades of research, scientists didn't know the exact mutation responsible for the once - unusual dark wings. (sciencemag.org)