Genomic tools for examining sex determining loci in the white marked tussock moth, Orgyia leucostigma (Lepidoptera: Erebidae: Lymantriinae)

The White marked Tussock moth (WMTM) (Orgyia leucostigma) is a generalist forest pest causes significant economic damage within its range. Adult males and females display extreme sexual dimorphism. While males have fully functional wings and can disperse, females are brachypterous, which limits the expansion of its geographic range. Understanding the genetic control and regulation of wing development requires an examination of the WMTM at all life stages, from first instar larvae to pupae. Unfortunately, it is not possible to identify sex in early larval instars using morphological approaches alone; a reliable approach using molecular tools would alleviate this problem. To accomplish this, we aimed to identify sex determining loci in the WMTM to develop a robust tool for identifying sex. For example, the gene doublesex is alternatively spliced during development, and should be diagnostic for sex using RT-PCR. We performed deep genome sequencing to assemble contigs that can be matched to known sex determining loci in related moths, such as Lymantria dispar. So far, we have identified 7 genes involved in sex determination and control in lepidopterans in the genome of the WMTM. These loci have been verified with using PCR amplification and Sanger Sequencing. We hope to also improve our current genomic assembly by obtaining long sequence reads via Nanopore sequencing of the WMTM. Here, we will report on the success of these approaches and characteristics of the WMTM genome assembly we have to date.