INSECT GENOMIC BIODIVERSITY AND MOLECULAR REGULATION OF DIAPAUSE
Location: Insect Genetics and Biochemistry Research
Title: Molecular phylogeny and genetic diversity of Lygus
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 21, 2009
Publication Date: April 1, 2008
Citation: Roehrdanz, R.L., Foottit, R.G., Burange, P., Maw, E., Boetel, M.A., Sears, S. 2008. Molecular Phylogeny and Genetic Diversity of Lygus. Astract. 2nd International Lygus Symposium, April 15-19, 2007. Journal of Insect Science Vol 8, Article 49, p. 24.
Inter- and intraspecific genetic diversity in North American Lygus was using nuclear and mitochondrial DNA. DNA sequences have been obtained from the mitochondrial cox1 and cox2 genes, the nuclear ITS1 spacer, and regions flanking microsatellites (MSFR). The Fargo lab sequenced a region overlapping the cox1-cox2 boundary, whereas the Ottawa lab sequenced a region near the 5-prime end of cox1. These data sets are being merged by reciprocal swapping and sequencing of key DNA samples.
L. lineolaris has been widely sampled in the eastern US and southern Canada. The cox1-cox2 boundary sequence divides into two major clades and a small third group of very divergent individuals. One of the MSFRs and cox1 together also form two clades. Preliminary data suggests that the two marker sets might be defining the same populations and at least raise the possibility of cryptic species within L. lineolaris. Well-defined geographic based population structure has not been uncovered in L. lineolaris.
The whole genus Lygus is monophyletic. At the interspecific level within the genus both ITS1 and MSFRs roughly divide the species into eastern and western groups. L. borealis goes east with ITS1 and west with MSFRs. Strict monophyly of the species has been difficult to demonstrate. With cox1-cox2 the majority of sequences from individuals identified as L. lineolaris, L. elisus, L. borealis, L. hesperus, and L. keltoni cluster together as species. However a few individuals from all of these species are scattered among other branches of the trees. Some of the non-pest species might be monophyletic, but the sample numbers are quite small. The small third group of L. lineolaris is most closely associated with L. borealis. The L. hesperus and L. keltoni clusters are intermixed in both cox1-cox2 and some MSFR.
The complete mt genomes (~14,200 bp), except for the control region have been sequenced from L. lineolaris (Roehrdanz) and L. hesperus (S Cameron, Australia). The nucleotide sequence divergence between them is about 3.5%. The L. hesperus mtDNA has two major deletions in two different protein coding genes.