Journal of Heredity Advance Access published online on January 18, 2009
Journal of Heredity, doi:10.1093/jhered/esn111
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Evolution of Microsatellite Loci in the Adaptive Radiation of Hawaiian Honeycreepers
From the Center for Conservation and Evolutionary Genetics, National Zoological Park and National Museum of Natural History, Smithsonian Institution, 3001 Connecticut Avenue NW, Washington, DC 20008 (Eggert, Beadell, McIntosh, and Fleischer); and Department of Zoology, University of Hawaii at Manoa, Honolulu, HI 96822 (McClung). Lori S. Eggert is now at Division of Biological Sciences, University of Missouri, 226 Tucker Hall, Columbia, MO 65211
Address correspondence to Lori S. Eggert, Biological Sciences, University of Missouri, 226 Tucker Hall, Columbia, MO 65211, or e-mail: eggertl{at}missouri.edu.
Previous studies have examined germ-line mutations to infer the processes that generate and maintain variability in microsatellite loci. Few studies, however, have examined patterns to infer processes that act on microsatellite loci over evolutionary time. Here, we examine changes in 8 dinucleotide loci across the adaptive radiation of Hawaiian honeycreepers. The loci were found to be highly variable across the radiation, and we did not detect ascertainment bias with respect to allelic diversity or allele size ranges. In examining patterns at the sequence level, we found that changes in flanking regions, repeat motifs, or repeat interruptions were often shared between closely related species and may be phylogenetically informative. Genetic distance measures based on microsatellites were strongly correlated with those based on mitochondrial DNA (mtDNA) sequences as well as with divergence time up to 3 My. Phylogenetic inferences based on microsatellite genetic distances consistently recovered 2 of the 4 honeycreeper clades observed in a tree based on mtDNA sequences but differed from the mtDNA tree in the relationships among clades. Our results confirm that microsatellite loci may be conserved over evolutionary time, making them useful in population-level studies of species that diverged from the species in which they were characterized as long as 5 Ma. Despite this, we found that their use in phylogenetic inference was limited to closely related honeycreeper species.
Key Words: ascertainment bias • dinucleotide repeats • genetic distance measures • honeycreepers • microsatellites • phylogenetic inference
Corresponding Editor: Oliver Ryder