The Genetics of Resistance to Morinda Fruit Toxin During the Postembryonic Stages in XXXX .

@entity12137 @entity375 @entity13271
UNASSIGNED: While a great deal has been learned of the genetic changes that give rise to adaptation in bacteria and @entity375 , an understanding of how new complex traits arise in multicellular organisms is far less complete. Many phytophagous insect species are ecological specialists that have adapted to utilize a single host plant. @entity13271 is a specialist that utilizes the ripe fruit of Morinda citrifolia, which is toxic to its sibling species, @entity12137 . Here we apply multiplexed shotgun genotyping and QTL analysis to examine the genetic basis of resistance to M. citrifolia fruit toxin in interspecific hybrids. We identify a locus of large effect on the third chromosome (QTL-IIIsima) in the @entity12137 backcross that was not detected in previous analyses. We also identify a highly significant QTL of large effect on the X chromosome, QTL-Xsim. Additional smaller-effect loci were also identified in the @entity12137 and @entity13271 backcrosses. We did not detect significant epistasis between loci. Instead, our analysis reveals large and smaller-effect loci that contribute to M. citrifolia resistance additively. The additive effect of each locus suggests that partial resistance to lower levels of M. citrifolia toxin could be passed through introgression from @entity13271 to @entity12137 in nature. The identification of the major effect loci, QTL-IIIsima and QTL-Xsim, is an important step towards identifying the molecular basis of adaptation in a multicellular organism.
