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71.
Sera from a total of 564 olive baboons collected at six different localities in west central Kenya were examined for the presence
of cross-reactive immunoglobulin allotypes with reagents used for human sera. Serum samples were tested for Km (1 and 3),
Glm (1–3 and 17), andG3m (5, 6, 10, 11, 13–16, 21, 24, and 26). Polymorphism was found for Glm (1 and 17) and G3m (10, 13,
and 15). These findings on antigen presence, absence, and polymorphism show broad similarities to, along with some differences
from, previous studies of baboons. Our data support the view that there are variations in allotype frequencies between troops
at single localities, as well as differences among geographically separated areas. Linkage disequilibria for Gm allotypes
differ in strength and direction among the various local Kenya olive baboon populations. 相似文献
72.
E. Nevo A. Beiles D. Kaplan N. Storch D. Zohary 《Plant Systematics and Evolution》1986,153(3-4):141-164
Genetic diversity and structure of populations of the wild progenitor of barleyHordeum spontaneum in Iran was studied by electrophoretically discernible allozymic variation in proteins encoded by 30 gene loci in 509 individuals representing 13 populations of wild barley. The results indicate that: a)Hordeum spontaneum in Iran is extremely rich genetically but, because of predominant self-pollination, the variation is carried primarily by different homozygotes in the population. Thus, genetic indices of polymorphismP-1% = 0.375, range = 0.267–0.500, and of genetic diversity,He = 0.134, range = 0.069–0.198, are very high. b) Genetic differentiation of populations includes clinal, regional and local patterns, sometimes displaying sharp geographic differentiation over short distances. The average relative differentiation among populations isGst = 0.28, range = 0.02–0.61. c) A substantial portion of the patterns of allozyme variation in the wild gene pool is significanctly correlated with the environment and is predictable ecologically, chiefly by combinations of temperature and humidity variables. d) The natural populations studied, on the average, are more variable than two composite crosses, and more variable than indigenous land races of cultivated barely,Hordeum vulgare, in Iran. — The spatial patterns and environmental correlates and predictors of genetic variation ofH. spontaneum in Iran indicate that genetic variation in wild barley populations is not only rich but also at least partly adaptive. Therefore, a much fuller exploitation of these genetic resources by breeding for disease resistance and economically important agronomic traits is warranted. 相似文献
73.
D. R. LEES C. S. DENT 《Biological journal of the Linnean Society. Linnean Society of London》1983,19(2):115-129
The visible polymorphism of the spittlebug, Philaenus spumarius, has been investigated in the vicinity of a smokeless fuel factory in the Cynon Valley of south Wales. The factory is a significant source of local particulate air pollution. A striking relationship exists between the combined frequencies of the eight dark (melanic) morphs and proximity to the factory. Maximum melanic phenotype frequencies of over 95“, occur in both sexes immediately adjacent to it and decline to levels normal for south Wales 1.5–6 km away, depending on direction. This relationship is largely confined to sites within the valley; samples from adjacent localities outside it have melanic frequencies within normal limits for the south Wales area. Maximum melanic phenotype frequencies in the Cynon Valley are far higher than any known from elsewhere in the species range in Europe, Asia and North America. No consistent difference is apparent in total melanic frequency between males and females at any of the sites in this study. However, marked differences exist between the sexes in the relative contributions of the eight melanic phenotypes to the overall association with the factory. For females the industrial melanism is entirely attributable to the group flanicollis + gibbus + leucocephalus (mainly leucocephalus) whereas in males both this group and the group quadnmaculatus + albomaculatus + leucopthalmus contribute to the relationship. It is suggested that this relationship is due to the selective effects of the local air pollution from the factory. The exact nature of the selection involved is as yet uncertain; it would appear to be strong since the local adaptation involved has developed in a maximum of 40 generations since the factory was opened. Finally, comparison is made with two other insects, a ladybird and a moth, in which high frequencies of melanic forms are also associated with this pollution source. 相似文献
74.
R. B. HALLIDAY N. H. BARTON † G. M. HEWITT 《Biological journal of the Linnean Society. Linnean Society of London》1983,19(1):51-62
We have made an extensive allozyme survey of 21 enzyme and protein loci in populations of the alpine grasshopper Podisma pedestris. This species occurs in two races, differing by a chromosomal fusion which separates the ancestral XO/XX race from a derived neo-XY race. These races also differ in DNA content, and hybrids between them have reduced viability. Electrophoresis reveals that the amount of genetic differentiation between these races is no greater than the variation among populations within each race. Both larger-scale surveys and a detailed survey of an area where the races hybridize, show that the chromosomal change is not correlated with gene frequency changes at any of the 21 loci studied. These findings are consistent with recently developed theory concerning the strength of the barrier to gene flow posed by a hybrid zone with characteristics such as those measured experimentally in Podisma. It is argued that hybrid zones in other species which involve allozymic differences do so because of stronger selection against hybrids rather than through mating isolation. 相似文献
75.
José Fayos Aurea Perales Mariano Pinar Manuel Rico Benjamín Rodríguez 《Phytochemistry》1983,22(9):1983-1984
The structure and absolute configuration of desangeloylshairidin, a guaianolide isolated from Guillonea scabra, have been established by X-ray diffraction analysis. No conformational change was observed in its seven-membered ring between the crystal and deuterochloroform solution states. 相似文献
76.
In order to regulate cell volume during hyperosmotic stress, the intertidal copepod Tigriopus californicus, like other aquatic crustaceans, rapidly accumulates high levels of intracellular alanine, proline, and glycine. Glutamate-pyruvate transaminase (GPT; EC 2.6.1.2), which catalyzes the final step of alanine synthesis, is genetically polymorphic in T. californicus populations at Santa Cruz, California. Spectrophotometric studies of homogenates derived from a homozygous isofemale line of each of the two common GPT alleles indicated that the GPTF allozyme has a significantly higher specific activity than the GPTS allozyme. Under conditions of hyperosmotic stress, individual adult copepods of GPTF and GPTF/S genotypes accumulated alanine, but not glycine or proline, more rapidly than GPTS homozygotes. When young larvae were subjected to the same hyperosmotic conditions, GPTS larvae suffered a significantly higher mortality than GPTF or GPTF/S larvae. These results suggest that the biochemical differences among GPT allozymes result in specific physiological variation among GPT genotypes and that this physiological variation is manifested in differential genotypic survivorships under some naturally occurring environmental conditions.This work was supported in part by a grant from the Lerner Fund for Marine Research of the American Museum of Natural History, an NIH Training Grant in Integrative Biology, and NIH Grants GM 28016 and GM 10452. 相似文献
77.
Olga O. Blumenfeld Anthony M. Adamany Karen V. Puglia Wladyslaw W. Socha 《Biochemical genetics》1983,21(3-4):333-348
Chimpanzee erythrocytes express strong M but weak, occasional N blood-group activity, as detected by anti-M and anti-N reagents. We have found that the M activity is carried by a major membrane glycoprotein that is similar but not identical to the human MM glycoprotein (glycophorin A). We have isolated and characterized this glycoprotein from erythrocyte membranes of four individual chimpanzees. The purified glycoproteins strongly inhibited agglutination of M cells by rabbit anti-human M sera and only weakly inhibited the agglutination of N cells by rabbit anti-human N sera. They also displayed medium-to-strong inhibitory activity against chimpanzee iso- and crossimmune antisera tested with chimpanzee erythrocytes of various V-A-B-D and Wc specificities, which are known as chimpanzee extensions of the human type M-N system and the Miltenberger counterpart, respectively. Each glycoprotein was cleaved with CNBr into three fragments, whose size, solubility, and composition were analogous to those obtained by similar treatment of the human M-N antigens. The amino-terminal fragment was found to be a glycooctapeptide whose amino acid composition and partial sequence indicated that it is an intermediate form of the human M and N glycooctapeptides. Its carbohydrate content comprised two threonine-linked saccharide units that, although similar in composition to the human threonine-linked units, were fewer in number than the three units found in the corresponding human glycooctapeptides. Structural similarities to the human antigens strongly suggest that the amino terminus bears the major antigenic determinants of the molecule, and the occurrence in this region of numerous, albeit rare, variants among humans and in chimpanzees indicates that the corresponding coding sequence of the structural gene is particularly susceptible to mutational events. We conclude that the chimpanzee M gene product is a variant of the human type and that the chimpanzee gene is an allele of the human polymorphic M-N locus.This research was supported by National Institutes of Health Grants GM 16389 and HL 19011 and March of Dimes Grant 1-661. 相似文献
78.
Conditions for the maintenance of males in androdioecious populations (populations with both male and hermaphrodite individuals) have been derived for four different one-locus two-allele models of inheritance of androdioecy. The results are not in general accordance with those already known: depending on the mode of inheritance, males can be maintained irrespective of their fertilities. If males are sufficiently fertile, it may happen that they are maintained only for intermediate selfing rates of the hermaphrodites. A result already found for gynodioecy is confirmed for androdioecy, namely, that a 11 sex ratio is immediately established among zygotes if hermaphrodites appear as heterozygotes only. 相似文献
79.
The results of 11 experiments with Drosophila species show that fertility is not a reducible property: the fertility of a mating pair cannot be predicted from the average fertility of the two genotypes involved. We propose a model of fertility selection that does not assume additivity (or multiplicativity) but assumes random mating and that the genotypic frequencies are in Hardy-Weinberg equilibrium. Numerical simulations show that removal of the assumption of Hardy-Weinberg frequencies does not significantly change the equilibrium frequencies predicted by the model. 相似文献
80.
Conformational fluctuations in a globular protein, bovine pancreatic trypsin inhibitor, in the time range between picoseconds and nanoseconds are studied by a Monte Carlo simulation method. Multiple energy minima are derived from sampled conformations by minimizing their energy. They are distributed in clusters in the conformational space. A hierarchical structure is observed in the simulated dynamics. In the time range between 10(-14) and 10(-10) seconds dynamics is well represented by a superposition of vibrational motions within an energy well with transitions among minima within each cluster. Transitions among clusters take place in the time range of nanoseconds or longer. 相似文献