Unusual mitochondrial genome in introduced and native populations of Listronotus bonariensis (Kuschel)

Abstract

The Argentine stem weevil is a serious pest of pasture and other graminaceous crops in New Zealand. Fifteen populations from South America, New Zealand and Australia were examined in an effort to determine the geographical origin of the species in New Zealand. Our previously reported RAPD analysis of these populations (Williams et al., 1994) revealed that the source of the pest was the Rio de la Plata on the east coast of South America. As a second approach to examining genetic variation, RFLP analysis of the mitochondrial genome, using the digoxigenin-labelled boll weevil mitochondrial genome as a probe, was also performed. The mitochondrial analysis revealed that the species possesses an unusually large mitochondrial genome of 32 kb, which exhibits extremely low levels of polymorphism both in the introduced and native populations. This low variation is in contrast with the informative level of inter-and intrapopulation variation revealed by RAPD.