Nuclear intergenic DNA sequence divergence in a Texas dwarf mistletoe (Arceuthobium divaricatum) population

Abstract

Arceuthobium divaricatum is a species of dwarf mistletoe that parasitizes six species of pinyon pine (Pinus subsec. Cembroides). Previous phylogeographic research discovered a population of A. divaricatum in the Guadalupe Mountains of Texas that had significant sequence divergence in intergenic regions of chloroplast DNA compared to all other populations. In this study, conserved regions of nuclear intergenic DNA from the same Guadalupe Mountains population and its two neighboring populations were amplified using PCR and then sequenced. The DNA sequences were edited and aligned to determine if there was a significant amount of nuclear sequence divergence. There is 3.8% nuclear sequence divergence between the Guadalupe Mountain population and its two neighboring populations, which is more than the 3.5% nuclear sequence divergence in two recognized subspecies of Arceuthobium vaginatum obtained from GenBank. Based on genetic information the divergent population may warrant further investigation to determine whether it might be better classified as its own subspecies.