FITNESS LOSS AND GERMLINE MUTATIONS IN BARN SWALLOWS BREEDING IN CHERNOBYL

The severe nuclear accident at Chernobyl in 1986 resulted in the worst reported accidental exposure of radioactive material to free-living o rganisms(1). Short-term effects on human populations inhabiting pollut ed areas include increased incidence of thyroid cancer(2), infant leuk aemia(3), and congenital malformations in newborns(4). Two recent stud ies(5,6) have reported, although with some controversy(7,8), that germ line mutation rates were increased in humans and voles living close to Chernobyl, but little is known about the viability of the organisms a ffected(9). Here we report an increased frequency of partial albinism, a morphological aberration associated with a loss of fitness, among b arn swallows, Hirundo rustica, breeding close to Chernobyl. Heritabili ty estimates indicate that mutations causing albinism were at least pa rtly of germline origin. Furthermore, evidence for an increased germli ne mutation rate was obtained from segregation analysis at two hyperva riable microsatellite loci, indicating that mutation events in barn sw allows from Chernobyl were two-to tenfold higher than in birds from co ntrol areas in Ukraine and Italy.