Showing papers by "John C. Avise published in 1976"
TL;DR: The results suggest that at least four, and possibly five of the genera of California minnows are very similar in genic content and are probably of recent monophyletic origin, and mean time since divergence from a common ancestor is more important than mean number of cladogenetic events in the evolutionary history of a group of species as a predictor of levels of biochemical differentiation.
Abstract: The systematics of cyprinid fishes native to California has had a chaotic history. Considerable controversy exists about the number of species, their placement in genera, and the evolutionary affinities among the genera (Uyeno, 1961; Hopkirk, 1973). About 16 species and 10 genera are recognized at present (Moyle, 1974). Five of these genera (Orthodon, Mylopharodon, Hesperoleucus, Lavinia, and Pogonichthys) are monotypic and restricted in distribution to a single drainage basin, the Sacramento-San Joaquin. All cyprinids in North America are thought to belong to the subfamily Leuciscinae with a single possible exception; several subfamilies are recognized in the Old World (Miller, 1959). It is commonly accepted that relatively few cyprinid fishes migrated from their center of origin in Eurasia to North America by way of a Bering land bridge during the Miocene. Therefore, most cyprinid species in North America, including the California minnows, may share a relatively recent common ancestry. "Not only the lack of basic morphological diversity but also the readiness with which most American minnows hybridize (Hubbs, 1955) supports the evidence that the group has not been here long enough to develop strongly divergent lines" (Miller, 1959). It has, nevertheless, been suggested that close affinities exist between certain Western cyprinid genera (Mylopharodon, Gila) and those in China and Japan (see Miller, 1965). We have analyzed patterns of genetic variability at 24 gene loci in species belonging to nine genera of cyprinids inhabiting California, using techniques of gel electrophoresis. These techniques provide considerable information to elucidate evolutionary relationships among closely related species (Avise, 1974). Our results suggest that at least four, and possibly five of the genera of California minnows are very similar in genic content and are probably of recent monophyletic origin. However, the other California minnows are less closely related, and the biochemical differences observed between these species may be typical of mean levels of divergence between other North American cyprinids. Models are considered which describe amounts of genetic differentiation expected between species within a group. One model assumes that genetic distance between species is proportional to the time since they shared a common ancestor; the other model assumes that genetic distance is proportional to the number of cladogenetic events (speciations) in the evolutionary history of the group. Those models lead to distinct predictions of mean amounts of genetic distance between species in speciesdiverse versus species-depauperate phylads of equal evolutionary age. Our data on the California minnows suggest that mean time since divergence from a common ancestor is more important than mean number of cladogenetic events in the evolutionary history of a group of species as a predictor of levels of biochemical differentiation.
112 citations
TL;DR: There is a significant correlation between ADH activities and survivorship on alcohol-treated media for these nine species, consistent with the interpretation that α-GPDH is involved with a relatively uniform adaptive function among species, whereas ADH levels may reflect variable adaptive capabilities.
Abstract: The activity levels of alcohol dehydrogenase and alpha-glycerophosphate dehydrogenase were compared among nine species of Drosophila representing three phylogenetic groups. For any given life stage , interspecific variability in activity level was much greater for ADH than for d-GPDH. Patterns of ontogenetic expression of enzyme activity were also much more variable among species for ADH than for alpha-GPDH. These results are consistent with the interpretation that alpha-GPDH is involved with a relatively uniform adaptive function among species, whereas ADH levels may reflect variable adaptive capabilities. There is a significant correlation between ADH activities and survivorship on alcohol-treated media for these nine species.
68 citations
TL;DR: The demonstration of significantly different patterns of plate development in intralocality versus interlocality crosses evidences a contrasting genetic basis for plate determination in different populations of sticklebacks.
Abstract: Author(s): Avise, JC | Abstract: A collection of Gasterosteus aculeatus from a single locality (Friant) in Madera County, California, contains individuals with low and high lateral plate morphology, and very few intermediates. Electrophoretic evidence on protein similarities at 15 genetic loci is compatible with the thesis that members of these two morphs belong to a single interbreeding population. This thesis is also supported by broods from laboratory crosses between morphs, which segregate for low and high plate counts. Laboratory crosses between Friant fish and those from geographically isolated populations often yield some progeny with intermediate plate counts. The demonstration of significantly different patterns of plate development in intralocality versus interlocality crosses evidences a contrasting genetic basis for plate determination in different populations of sticklebacks. © 1976, Cambridge University Press. All rights reserved.
43 citations
TL;DR: A single triploid individual (3n = 75) of the Calfornia roach, Hesperoleucus symmetricus, was identified among a sample of nine specimens from the Russian River, California, which is the first report of aTriploid fish from the wild, and the second report in a bisexual fish species.
Abstract: A single triploid individual (3n = 75) of the Calfornia roach, Hesperoleucus symmetricus, was identified among a sample of nine specimens from the Russian River, California. The diploid number of H. symmetricus, as revealed by the karyotypes of the remaining eight specimens, is 50. Aside from the all-female triploid unisexual fishes, this is the first report of a triploid fish from the wild, and the second report of a triploid in a bisexual fish species. The most likely origin of the triploid was probably fusion of a haploid sperm with an unreduced ovum.
32 citations
TL;DR: Enzyme levels parallel the distinct morphological and physiological changes characterizing development of representative holo- and hemi-metabolic insects.
Abstract: 1. 1. Several carbohydrate metabolizing enzymes were examined spectrophotometrically and electrophoretically in four life stages of the holometabolic fruit fly, Drosophila pseudoobscura , and in three life stages of the hemimetabolic pea aphid, Acyrthosiphon pisum . 2. 2. Drosophila pupae exhibit significantly lower enzyme activities than third instar larvae. Most enzymes recover to larval levels or higher in adults, but some continue to decrease following eclosion. 3. 3. Enzyme activities remain relatively unchanged during development of Acyrthosiphon . 4. 4. The same isozymic forms of each enzyme are usually represented in all life stages of Drosophila , and in all life stages of Acyrthosiphon . 5. 5. Enzyme levels parallel the distinct morphological and physiological changes characterizing development of representative holo- and hemi-metabolic insects.
23 citations