Protein Variation in Several Species of Hyla

Abstract

Case, S. M., Haneline, P. G., and M. F. Smith (Museum of Vertebrate Zoology, University of California, Berkeley, California 94720) 1975. Protein variation in several species of Hyla. Syst. Zool. 24:281-295.-Allelic variation at fourteen loci coding for ten enzymes was studied in seventeen populations of Hyla regilla and in H. eximia, H. wrightorum, H. cadaverina, and H. euphorbiacea. Heterozygote deficiencies were found at several loci in several populations of H. regilla and possible reasons are suggested. The proportion of polymorphic loci and average individual heterozygosity were typical of other vertebrates with some exceptions: (1) the Lee's Camp, Oregon population; (2) the Santa Cruz Island population; (3) the three San Diego Co. populations; (4) the Sierra San Pedro Martyr population; and (5) the three populations in southern Baja California. Measures of genetic similarity (S) and genetic distance (D), as well as patterns of variation in allele frequencies at PGI and IDH-2, suggested three groups within Hyla regilla. These were: (1) the four Oregon populations; (2) the three central California populations; and (3) the ten southern California and Baja populations. The proportion of major alleles shared indicated Hyla eximia and H. wrightorum, are very closely related and that H. wrightorum is not a subspecies of H. regilla; H. eximia and H. wrightorum are also closely related to H. euphorbiacea. Hyla regilla and H. cadaverina are more closely allied to each other than they are to the other three forms. A strong correlation (r = 0.93) between genetic relatedness as measured by immunological comparisons of albumin and that measured by electrophoretic studies of many proteins was found, although immunological techniques cannot be used to study taxa which are very closely related (D = 0.25 or less). [Proteins; genetics; Hylidae] Since the pioneering work of Lewontin & Hubby (1966) attention has been focused on the amount and significance of genic variation in local populations. Subsequently electrophoresis has been used to study various aspects of local population genetics and the relationships among species (see Selander & Johnson, 1973 for a review). A number of electrophoretic studies of anurans have been conducted (Dessauer & Nevo, 1969; Gartside, 1972; Guttman & Wilson, 1973; Maxson & Wilson, 1974a; Platz & Platz, 1973; Rogers, 1973a and b; Salthe, 1969; Salthe & Nevo, 1969). The scope of these works is wide, ranging from an analysis of variation at a few loci as a method of assessing amounts of introgression to a survey of variation at a large number of loci in an effort to determine the overall level ' California Academy of Sciences, San Francisco, California; Present address: Department of Amiphibians and Reptiles, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138. of genic variation and to examine genetic relationships between two or more forms. No detailed study of the latter type has been done with any members of the genus Hyla. The main purpose of this study was to determine the amount of genic variation within and the genetic distance between populations of Hyla regilla. This is of particular interest since this species ranges from British Columbia to the tip of Baja California and has been divided into ten subspecies by Jameson, et al. (1966) on the basis of a discriminate analysis of morphological characters. Maxson & Wilson (1974b) have compared the serum albumins of eight of these subspecies using the method of microcomplement fixation. Electrophoretic estimates of genetic distance can provide an independent method for detecting subgroups within this wide-ranging species. In addition, several other members of the Hyla eximia group, in which H. regilla