Mitochondrial ancient DNA analysis of Lawson cave black bears (Ursus americanus)

Abstract

The distribution of black bear (Ursus americanus) in southern and central Missouri has been controversial. This controversy centers on two questions: 1) Where does the historical species fit into the continental phylogeography; 2) Are the contemporary black bears native to the region, or the result of an in-migration of black bears translocated into Arkansas? To answer these questions I extracted DNA from 10 black bears, collected from Lawson Cave, an Historical Era (0-550 year old) site in central Missouri. These bears are the most recent samples that can be unambiguously identified as native to Missouri. I successfully amplified the control region of the mitochondria of four of the 10 samples. Two of the four samples are exact matches to a known haplotype, extending from Minnesota to Mexico. Using modern samples and sequences from central North America I created a phylogeny that grouped into two clades. All of the samples from Lawson Cave grouped into clade 1. This suggests that this clade is recently native to Missouri. I also compared samples collected from a study of modern Missouri black bears. These bears fell into both clade 1 and clade 2. This study was unable to determine whether certain modern bears belong to clade 1 as a result of in situ mitochondrial continuity, or because of the widespread distribution of this clade throughout central North America. These results suggest that although certain bears belong to a clade native to Missouri, many also belong to a group not known from Missouri's historic past.