Gene expression in two Hawaiian honeycreeper populations

Introduced pathogens exert string selection on hosts. For instance, mosquitoes and Plasmodium relictum introduced to Hawaii have resulted in extinctions and catastrophic population declines of Hawaiian honeycreepers due to avian malaria. However, some populations of the Hawai'i 'amakihi (Chlorodrepanis virens) can survive infection. Immunity exists in low-elevation populations where mosquitoes are abundant, whereas high-elevation populations of 'amakihi demonstrate reduced immunity. To explore the basis of adaptation to P. relictum in low-elevation 'amakihi, we sequenced transcriptomes from 24 low-elevation and 15 high-elevation 'amakihi. We tested for differential gene expression between (i) infected and uninfected birds and (ii) low- and high-elevation birds.