Spatial, Temporal, and Age-Dependent Heterozygosity of Beta-Hemoglobin in White-Tailed Deer

Abstract

Genotypic proportions and heterozygosity of beta-hemoglobin in a white-tailed deer (Odocoileus virginianus) herd were secured to estimate the association of sex, location, year, and age with the variability of this locus. No differences (P > 0.05) in heterozygosity or genotypic frequencies occurred between sexes or among 5 regions on the Savannah River Plant. Heterozygote proportions among 2,455 deer varied (P 3.5 years) had higher (P < 0.05) frequency of heterozygotes than those of younger age-classes. The association of age and heterozygosity did not differ among regions or between years. Because age is an important determinant of social status in deer, shifts in the age structure of the herd may increase competitive interactions and, thus, be the source of selection for the changes in heterozygosity. J. WILDL. MANAGE. 46(4):983-990 Genetic variability in the white-tailed deer is higher than in other large mammals (Smith et al. 1976). Natural selection helps maintain genetic variability in this species, because the type, direction, and intensity of selection vary through space and time (Baccus et al. 1977). Important characters such as reproduction, aggressive behavior, and survivorship in birds and mammals are associated with heterozygosity (Krebs et al. 1973; Smith et al. 1975, 1978; Garten 1976; Johns et al. 1977; Baker and Fox 1978). These characters are intimately associated with the efficiency of resource use, and resource limitation may be the source of selection for heterozygosity. Differential selection of animals from various cohorts, sexes, or age-classes could also cause high heterozygosity in deer. Susceptibility to disease and competitive ability for limited resources also differ among life stages (Verme 1977). Few studies have documented genetic changes with age. Tinkle and Selander (1973) found age-specific selection respons ble for changes in genotypic proportions in a lizard population; heterozygosity was considerably higher in the oldest age-class. In white-tailed deer, no genetic differences for beta-hemoglobin (PHB) were found among animals of different ages from Iowa and Nebraska (Miller et al. 1965). However, Ramsey et al. (1979:139) reported age-specific differences in the heterozygosity of PHB in de r from the Savannah River Plant (SRP). Deer of each sex and age-class are also characterized by different gene frequencies for other loci (Manlove et al. 1975, Ramsey et al. 1979). Thus, a deer herd seems to be composed of genetically heterogeneous groups but this point needs further documentation. The objectives of our study were to test 4 null hypotheses. These were that genotypic proportions of beta-hemoglobin in white-tailed deer do not vary between sexes, and among ageclasses, regions of the SRP, and years. We thank personnel of the U.S. For1 Present address: Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409. J. Wildl. Manage. 46(4):1982 983 This content downloaded from 157.55.39.159 on Sun, 18 Sep 2016 05:44:40 UTC All use subject to http://about.jstor.org/terms 984 HETEROZYGOSITY IN WHITE-TAILED DEER * Chesser et al. estry Station, SRP and our colleagues at the Savannah River Ecology Laboratory for help in the field. Financial support came from contract DE-AC09-76SR00819 between the U.S. Department of Energy and The University of Georgia.