Invasion facilitates hybridization with introgression in the Rattus rattus species complex

• Main Authors: Justin B. Lack, Daniel U. Greene, Chris John Conroy, Meredith J. Hamilton, Janet K. Braun, Michael A. Mares, Ronald A. Van Den Bussche
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: hybridizat; Rattus rattus
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.362.8628; http://www.eebweb.arizona.edu/nachman/Suggested Papers/Lab_papers_fall_12/lack_etal_2012.pdf

Biological invasions result in novel species interactions, which can have significant evolutionary impacts on both native and invading taxa. One evolutionary concern with invasions is hybridization among lineages that were previously isolated, but make secondary contact in their invaded range(s). Black rats, consisting of several morphologically very similar but genetically distinct taxa that collectively have invaded six continents, are arguably the most successful mammalian invaders on the planet. We used mitochondrial cytochrome b sequences, two nuclear gene sequences (Atp5a1 and DHFR) and nine microsatellite loci to examine the distribution of three invasive black rat lineages (Rattus tanezumi, Rattus rattus I and R. rattus IV) in the United States and Asia and to determine the extent of hybridization among these taxa. Our analyses revealed two mitochondrial lineages that have spread to multiple continents, including a previously undiscovered population of R. tanezumi in the south-eastern United States, whereas the third lineage (R. rattus IV) appears to be confined to Southeast Asia. Analyses of nuclear DNA (both sequences and microsatellites) suggested significant