Bessie Smith died on April 26, 1937.
Period -LRB- per -RRB- is a gene located on the X chromosome of Drosophila melanogaster .. Drosophila melanogaster. Drosophila melanogaster. Oscillations in levels of both per transcript and its corresponding protein PER have a period of approximately 24 hours and together play a central role in the molecular mechanism of the Drosophila biological clock driving circadian rhythms in eclosion and locomotor activity .. Oscillations. Oscillation ( cell signaling ). Mutations in the per gene can shorten -LRB- perS -RRB- , lengthen -LRB- perL -RRB- , and even abolish -LRB- per0 -RRB- the period of the circadian rhythm .