George C. Gorman

Genetic Distance and Heterozygosity Estimates in Electrophoretic Studies: Effects of Sample Size

itors. M. Borgers and M. De Brabander (eds.). North-Holland, Amsterdam. WARING, H. 1963. Colour change mechanisms of cold-blooded vertebrates. Academic Press, N.Y. WIKSWO, M. A., AND R. R. NOVALES. 1969. The effect of colchicine on migration of pigment granules in the melanophores of Fundulus heteroclitus. Biol. Bull. 137:228-237. , AND . 1972. The effect of colchicine on microtubules in the melanophores of Fundulus heteroclitus. J. Ultrastruct. Res. 41:189-201. WINGE, 0., AND E. DITLEVSEN. 1947. Colour inheritance and sex determination in Lebistes. Heredity 1:65-83.

GENETIC DIVERGENCE AMONG FISHES OF THE EASTERN PACIFIC AND THE CARIBBEAN: SUPPORT FOR THE MOLECULAR CLOCK

The concept of a molecular clock is certainly controversial among evolutionary biologists. Simply stated, the hypothesis predicts that the rate of amino acid substitutions between any pair of taxa is relatively regular and reflects the divergence time between the taxa. The substitutions can be measured directly, by sequencing proteins, or indirectly, by such techniques as immunological or electrophoretic comparisons. The molecular clock is a prediction of the neutrality hypothesis of molecular evolution. Under this hypothesis, the long-term rate of protein sequence evolution equals the rate of mutation which produces selectively equivalent amino acid substitutions in proteins. Since mutation rate is a stochastic process, the clock is viewed as stochastic (Kimura and Ohta, 1971). Much of the evidence in favor of the molecular clock has been reviewed by Wilson et al. (1977). By constructing phylogenetic trees from molecular data and comparing the amount of change occurring along diverging branches of the trees (relative rate test), Wilson et al. (1977) point out that one can assess the degree of regularity of molecular change between taxa. A useful clock has to be not only regular, but also must be calibrated. Calibration is not always easy to achieve, for it is dependent upon a knowledge of geological events, often the fossil record, and interpretations based upon such records are often open to considerable question (Carl-

EVOLUTIONARY GENETICS OF INSULAR ADRIATIC LIZARDS

eters of populations. In this paper we employ this technique in an analysis of the evolutionary genetics of the genus Lacerta in the Adriatic region. We compare genetic similarity among populations and species to obtain a quantitative estimate of related

Phenoxyethanol: Protein Preservative for Taxonomists

Pieces of chicken heart or skeletal muscle were placed in a dilute solution of the antimicrobial agent 2-phenoxyethanol and stored at room temperature. Under these conditions, the serum albumin, lactate dehydrogenase, and malate dehydrogenase in these tissues survived in easily detectable amounts for at least 2 weeks. The surviving proteins appeared to be identical with those of fresh tissues in physical, catalytic, and immunological properties. Phenoxyethanol also preserved heart and muscle proteins of representatives of other vertebrate classes. Tissue samples collected in the analysis by biochemical taxonomists.

Anolis Lizards of the Eastern Caribrean: A Case Study in Evolution. II. Genetic Relationships and Genetic Variation of the Bimaculatus Group

Gorman, G. C., and Y. 1. Kim (Biol. Dept., UCLA, Los Angeles, California 90024) 1976. Anolis lizards of the eastern Caribbean: a case study in evolution. II. Genetic relationships and genetic variation of the birnaculatus group. Syst. Zool. 25:62-77.-Anolis lizards of the northern Lesser Antilles were studied with starch gel electrophoresis. A total of 22 genetic loci was analyzed for 15 populations. These data were used to estimate genetic distance between populations, and genetic variation within populations. Genetic distance estimates between populations are considerably lower than the estimates for the ecologically equivalent Anolis roquet species group of the southern Lesser Antilles. The relative proximity of islands in the northern part of the archipelago increases the probability of multiple colonizations, hence introgression, and a relatively slower rate of genetic divergence. The data also suggest that the northern bimaculatus group is evolutionarily younger than the roquet group, hence has had less time for genetic divergence. There is a geographic pattern discernible in the genetic distance data. One very tight cluster involves the southernmost populations studied from Dominica, Guadeloupe, Marie Gallante, and Montserrat; a second cluster includes more northern forms from Redonda, Saba, and St. Martin. Variability is lowest on the three smallest islands, but beyond that, there is no correlation between island size and heterozygosity. Relative degree of heterozygosity may be related to colonization history. Source populations tend to have higher variability than derived populations. The degree of genetic differentiation as estimated electrophoretically is very poorly correlated with differentiation for morphological characters such as body size, color, or pattern. [Anolis; genetic relationships; heterozygosity; variability; biogeography; colonization]

Genotypic Evolution in the Face of Phenotypic Conservativeness: Abudefduf (Pomacentridae) from the Atlantic and Pacific Sides of Panama

patterns. Also, since the collecting sites are permanent ponds, it will be possible to screen larvae for their LDH patterns and determine if heterozygotes are represented in greater numbers in these earlier stages. Finally, a more extensive survey may uncover variants for the H monomer, since these seem to predominate or can be found in equal frequencies with M variants in anuran species (Maxson and Wilson, 1974; Salthe, 1969; Salthe and Nevo, 1969).

Genetic Relationships of Three Species of Bathygobius from the Atlantic and Pacific Sides of Panama

Electrophoretic study of 26 gene loci was carried out on Bathygobius soporator from the Atlantic side of Panama, and B. ramosus and B. andrei from the Pacific side of Panama. The most closely related pair is B. soporator and B. andrei. The predicted divergence time is about 2.5 million years, which is in accord with geological evidence on the rise of the Panama land bridge. B. ramosus is the distant member of the trio, about equidistant from the other pair.

Competitive exclusion between insular Lacerta species (Sauria, Lacertidae)

SummaryCompetetive exclusion between Lacerta sicula and L. melisellensis characterizes the small islands of the Adriatic Sea.In 1958 and 1959 M. Radovanovié introduced Lacerta sicula or Lacerta melisellensis onto islands exclusively occupied by the other species. During the summer of 1971 follow-up observations were made on three of these islands, two of which completely lacked representatives of the introduced species. On the third island, the introduced species appears to be replacing the native form. Minor habitat differences permit coexistence, however the situation is dynamic and probably not at equilibrium. A reciprocal introduction involving the two species on the islands of Pod Kopiŝte and Pod Mrĉaru is announced.

CHROMOSOMAL HETEROMORPHISM IN SOME MALE LIZARDS OF THE GENUS ANOLIS

Chromosomal heteromorphism in males of several species of the lizard genus Anolis is demonstrated. In the bimaculatus group, the diploid number of chromosomes is 29 in males and 30 in females. Males have three unpaired chromosomes--an acrocentric, a microchromosome, and a metacentric. These are interpreted as X1, X2, and Y, respectively. Females are characterized as X1X1X~2X2. In A. conspersus the male has a heteromorphic pair of macrochromosomes (one member is acrocentric, one member metacentric). The diploid number is 30. No female was available. A. biporcatus has a mechanism that appears identical to the bimaculatus group. The diploid number for males is 29, for females 30. Males have three unpaired chromosomes--an acrocentric, a microchromosome, and a metacentric. Males are X1X2Y, females are X1X1X2X2.

Population genetics of a "colonising" lizard: natural selection for allozyme morphs in Anolis grahami.

SummaryAllozyme frequencies of Anolis grahami from Bermuda were compared to those from Jamaica. These lizards were introduced into Bermuda from Jamaica in 1905. The magnitude of the genetic changes were consistent with the hypothesis that these changes were produced by random genetic drift. The changes for the separate alleles were, however, more heterogeneous than expected if caused by random drift alone. It is concluded that not all the alleles examined have been selectively neutral.