Genic Variability in the Raccoon Procyon lotor

Abstract

Starch-gel electrophoresis was used to study genic variation in the raccoon, Procyon lotor. Two hundred and forty-two specimens were analyzed from 14 localities in the United States. Polymorphism was observed at 10 of 23 loci, and mean heterozygosity varied from 0.07O to 4.37O. Results of F-statistic analyses indicated significant differentiation among localities at a majority of the polymorphic loci. Mean FST value of 37.47O was high in comparison to other mammals; however, FST values of 20.8%7O for eastern localities and 7.2%7O for northwestern localities were comparable to those reported for other mammals. Rogers' genetic similarity coefficient ranged from 0.801 to 0.994. Among localities within geographic regions, P lotor exhibited high genetic similarity; however, there was interlocality heterogeneity between specimens from eastern and northwestern regions. INTRODUCTION The raccoon, Procyon lotor, has been the subject of many biological investigations (Lotze and Anderson, 1979). However, with the exception of Dew and Kennedy (1980) and Beck and Kennedy (1980), who found little genic differentiation among populations of P lotor and low levels of heterozygosity in comparison with other mammals, little information is available concerning the genetics of this species. Both previous studies concentrated on raccoon populations in the southeastern United States. Dew and Kennedy (1980) suggested that artificial dispersal (relocation of 1 lotor through the pet trade and for recreational hunting and other purposes), coupled with a high potential for natural dispersal, may have allowed populations of this species in the Southeast to become highly similar genetically. Regions completely free of human influence on P lotor are difficult to document and may not exist. However, regions outside the southeastern United States probably have experienced less artificial dispersal because raccoons are not used as extensively for recreational purposes. The present study was designed to determine the degree of genetic differentiation among P lotor from various geographic areas in the United States and should support or dispute previous findings that suggest raccoons are genetically similar throughout their range. MATERIALS AND METHODS Liver and kidney samples of 242 Procyon lotor from Tennessee (TN, N = 56), Kentucky (KY, N = 56), Illinois (IL, N = 10), Wisconsin (WI, N = 8), Louisiana (LA, N = 7), Arkansas (AR, N = 11), Washington (WA, N = 4) and Oregon (OR, N = 90) were examined with horizontal starch-gel electrophoresis. Electrophoretic procedures were similar to those of Selander et al. (1971); detailed information concerning the buffer system for each locus is given in Hamilton (1984). Staining procedures were those of Selander et al. (1971) except where otherwise noted. Twenty-three presumed structural loci examined were as follows: alcohol dehydrogenase (Adh), albumin (Alb), acid phosphatase (Ap; Harris and Hopkinson, 1976), aspartate aminotransferase-l and -2 (Aat-l, -2), esterase-l, -2 and -3 (Es-l, -2, -3), glucophosphate isomerase (Gpi), glutamate dehydrogenase -(Gtdh; Shaw and Prasad, 1970) alpha-glycerophosphate dehydrogenase (Gpd), isocitrate dehydrogenase (Icd-l), lactate dehydrogenase-l and -2 (Ldh-l, 2), malate dehydrogenase-l and -2 (Mdh-l, -2), malic enzyme-l (Mod-l; Harris and Hopkinson, 1976), mannose phosphate isomerase (Mpi; Nichols et al., 1973), 'Present address: Department of Biological Sciences, Texas Tech University, Lubbock, 79409.