Achroia grisella strain:LA 112 Phenotype or Genotype

Male Achroia grisella generate an acoustic mating signal, and a series of studies have demonstrated that a male's attractiveness towards females is determined by specific characteristics of this song. Since these features are genetically-variable in populations, laboratory genetic mapping experiments have been used to identify and describe loci contributing to song variation, and have helped to understand the evolutionary forces that shape variation for this important sexual trait. Here, we build on this foundation, and carry out QTL (Quantitative Trait Locus) mapping using >1,000 recombinant individuals. We genotype this large cohort using thousands of sequence-based markers that cover the entire collection of 30 A. grisella chromosomes. This high-density marker set, coupled with our development of an annotated, draft genome of A. grisella, allowed us to link >3,000 genome scaffolds, >10,000 predicted genes, and close to 275Mb of genome sequence to chromosomes. Our QTL mapping confirmed a fraction of the QTL that were identified in a previous study, and additionally revealed novel loci. Collectively, QTL explain only small fractions of the phenotypic variance, suggesting many more causative factors remain below the detection threshold of our study. A surprising, and ultimately challenging feature of our study was the low level of intrachromosomal recombination present in our mapping population. This led to difficulty ordering markers along linkage groups, necessitated a chromosome-by-chromosome mapping approach, rather than true interval mapping, and precluded confident ordering/orienting of scaffolds along each chromosome. Regardless, we have increased the genetic and genomic resources available for the A. grisella system. Future investigators will be able to leverage our data, enabled by ever more powerful genomic technologies, to provide a more detailed genetic dissection of male song variation in A. grisella.