| molecular evidence against phylogenetically distinct host races of the pea aphid (acyrthosiphon pisum). | pea aphid (acyrthosiphon pisum) clones have been shown to be adapted to particular host plant species but it is unknown whether there are host races. a 1101 base pair region of the mitochondrial cytochrome oxidase i gene (coi) was sequenced for 21 pea aphid clones that had been collected from different host plants in canada and the u.s.a. only five closely related mitochondrial haplotypes were found. a maximum likelihood phylogeny was estimated for these five haplotypes and four related aphid sp ... | 1998 | 9924789 |