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1.
The composition of fatty acids in the tissue of heart, gill and skull oil of the three redfish species, Sebastes viviparus, Sebastes marinus and Sebastes mentella was determined by a chemometric method. The method consists of methanolysis of samples of the tissues and of the oils, gas chromatography of the resulting fatty acid methyl esters and multivariate statistical treatment, by principal component analysis, of the analytical data. Although the differences in fatty acid composition among the three tissues were the dominating features of the data, the three species had significantly different fatty acid profiles within each tissue, even though variation among the individuals was considerable. The fatty acid profiles appear to be species specific. The mutual relationship between S. marinus and S. mentella is closer than the relationship between either of them and S. viviparus.  相似文献   

2.
The fatty acid profile in the tissue of heart, gill, skull- and otolith-oil of the three redfish species, Sebastes viviparus, S. marinus and S. mentella was determined by a chemometric method, consisting of methanolysis of samples of the tissues and of the oils and gas chromatography of the resulting fatty acid methyl esters. The analytical data were treated by multivariate statistics comprising principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). Although the differences in fatty acid composition among the two tissues and two oils were the dominating features of the data, the three species had significantly different fatty acid profiles within each tissue. Variation among the individuals was considerable. The fatty acid profiles appeared to be species specific. The mutual relationship between S. marinus and S. mentella is closer than the relationship between either of them and S. viviparus. A comparison with a corresponding investigation on the same three species from another location indicates that the observed differences do not seem to be affected by biotic or abiotic factors.  相似文献   

3.
Significant body shape differences were observed between two commercially important redfish species Sebastes fasdatus and Sebastes mentella , in the Gulf of St Lawrence, first classified according to the variability at the MDH-A* locus, a diagnostic criterion for the two species in allopatry. The observed sexual dimorphism was probably related to the presence of gravid females in the sample. Sebastes mentella appeared to be more fusiform than S. fasdatus , a characteristic that may reflect the more pelagic behaviour of S. mentella . The body shape of their hybrids was closer to that of S. mentella . Similarities between hybrids and S. mentella were also observed for meristic characteristics and depth distribution. The implications of these similarities for introgression are discussed. Body shape variability of specimens of hybrid origin was greater than that of either parental species, with features ranging from S. mentella-like to S. fasciatus -like. The role of introgression in generating morphological variability is emphasized.  相似文献   

4.
Orosomucoid (ORM) or alpha-1-acid glycoprotein is an acute-phase protein of human plasma whose function is suggested to be the competitive inhibition of cellular recognition by infective agents. Genetically determined variation in ORM has been reported, with two major alleles segregating in all populations studied to date. Isoelectric focusing-immunoblotting studies of ORM revealed the presence of isoprotein species that did not segregate with the predominant alleles at the ORM locus and suggested the expression of a second structural gene locus for orosomucoid (ORM2). Genetically independent variation consistent with expression of the ORM2 locus was observed in plasma samples from American blacks but was not observed in U.S. whites or sampled populations of North- and South-American Indians, Eskimos, Aleuts, or New Guinea Highlanders. The population allele frequencies for this locus were .958, .025, .006, and .011 for alleles ORM*1, ORM2*2, ORM2*3, and ORM2*4, respectively. Family studies confirm the autosomal codominant inheritance of the observed phenotypes.  相似文献   

5.
The joint distributions of phenotypes from the apolipoprotein E gene (APOE) and from a closely linked restriction site polymorphism at the apolipoprotein C1 locus (APOC1) were studied in population samples from Portugal and S?o Tomé e Príncipe (Gulf of Guinea), a former Portuguese colony that was originally populated by slaves imported from the African mainland. The frequencies of the APOE alleles (*2, *3, and *4) in Portugal and S?o Tomé fitted the ranges of variation generally observed in European and African populations, respectively. Haplotype analysis showed that in both populations the strength of linkage disequilibrium was highest for the APOE*2 allele and lowest for the APOE*4 allele, suggesting that the origin of the APOE alleles followed a 4-->3-->2 pathway and thus providing independent confirmation of the results from sequence homology studies with nonhuman primates. In accordance with global trends in the distribution of human genetic variation, the European sample from Portugal presented more intense linkage disequilibrium between APOE and APOC1 than the African sample from S?o Tomé where, despite the short 4-kb distance that separates the 2 loci, the level of association between the APOC1 alleles and APOE*4 was nonsignificant.  相似文献   

6.
Fertilized eggs of Sebastes schlegelii, Sebastes pachycephalus and Sebastes hubbsi are morphologically similar under stereomicroscope. However, under the scanning electron microscope, significant differences in the ultrastructures of the egg surface among the three species were observed, and herein, a taxonomic key was proposed for future applications. A clustering analysis based on the ultrastructures of the egg surface and the diameter of the oil globule suggested that among the three species, S. hubbsi and S. pachycephalus were more genetically similar, while S. schlegelii had diverged earlier. The results agree with the conclusions drawn from morphological and molecular analyses on adult samples of the same species.  相似文献   

7.
Samples of salmon Salmo salar from the River Kachkovka and the River Nilma in northern Russia were analysed by starch gel electrophoresis and compared to three Norwegian stocks, the Neiden river in northern Norway and Øyreselv and Hopselv rivers on the west coast. The comparison included the following polymorphic loci: AAT-4 *, IDDH-2 *, IDHP-3 *, MDH- 3,4 *, MEP-2 *, ESTD * as well as the newly discovered polymorphic loci FBALD-3 * and TPI-3 *. Samples were run side by side on gels, and the alleles found in the Russian stocks were the same as those found in the Norwegian stocks, although the electrophoretic methods used lead to differences in designations of alleles. A polymorphism in ESTD * which involves a slow allele was commonly observed in the three northern populations of the Nilma, Kachkovka and Neiden rivers. This allele was absent in the other Norwegian stocks and in a major brood stock of farmed salmon in Norway. The IDHP-3 * 116 allele was found in unusually high frequencies in the northern populations. Thus, the variability observed at these two loci indicates a barrier to gene flow between the northern salmon stocks and the more southern stocks in the East Atlantic area.  相似文献   

8.
Isoelectric focusing and immunoblotting reveals considerable biochemical and genetic variation in the C1R subcomponent of the first complement component. The nature of the intraindividual biochemical variation can be explained by differences in sialic acid content because after digestion with neuraminidase the terminal sialic acids are removed to yield a single major band corresponding to the C1R polypeptide. Plasma samples from a large number of different ethnic groups, consisting of U.S. whites, U.S. blacks, Nigerian blacks, and Inuit, Aleut, and Amerindian populations from the Western Hemisphere have revealed genetically determined charge variation with heterozygous phenotypes consisting of two major asialo bands, indicating that the underlying variation is not due to variation in sialic acid content. Two previously reported common alleles, C1R*1 and CIR*2, have been observed in all studied populations, the notable exception being the Dogrib Indian population, which is devoid of the C1R*2 allele. Several new alleles--designated C1R*3, C1R*4, C1R*5, C1R*6, and C1R*7-have been observed, with variable frequencies ranging from the occurrence in a single individual and related family members to the polymorphic occurrence of certain alleles in several populations. Of these new alleles, the C1R*5 is of considerable interest in population and anthropological genetics studies. The C1R*5 allele is widely distributed, at a frequency of .03 to .17, in all of the North American aboriginal populations screened. This allele is not present in U.S. whites but is present at a polymorphic frequency in U.S. and Nigerian blacks.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

9.
On the ultrastructure of specific heart granules in teleosts   总被引:1,自引:0,他引:1  
The ultrastructure and chemical reactivity of teleostean specific ('atrial') heart granules (SHG) are described. In atrial cells of Glyptocephalus cynoglossus and Gadus morhua , large aggregations of SHG occur in areas of the sacroplasm rich in glycogen and poor in myofibrils. The SHG often appear to be in a process of lysis. A number of heart granules were also noted in atrial cells of Cichlasoma meeki, Pistella riddlei and Sebastes viviparus . although large aggregations were not seen. The mean diameters of SHG in G. cynoglossus and S. viviparus are 110 and 210 nm, respectively. SHG are regularly found in ventricular cells, although less frequently than in the atrium. Ultrahistochemical tests suggest that the teleostean SHG mainly contain proteins.  相似文献   

10.
We used mitochondrial DNA sequence variation of Sebastes from the southeastern Pacific and three localities in the South Atlantic to address long-standing systematic and evolutionary issues regarding the number of species in the Southern Hemisphere. Sequences of the hypervariable mitochondrial control region were obtained from 10 specimens of S. capensis from South Africa (n = 5) and from Tristan da Cunha Island (n = 5) and 27 of S. oculatus from Valparaiso, Chile (n = 10), and the Falkland Islands (n = 17). Results of the study include (1) significant levels of genetic differentiation among the sampled populations (phi ST = 0.225, P < .000001), thus indicating limited gene flow; (2) corroboration of the existence of two different lineages of austral Sebastes corresponding to S. capensis and S. oculatus; (3) finding that S. capensis is not restricted to Tristan da Cunha and South Africa, but is widespread across the South Atlantic; (4) the position of S. capensis as the ancestral lineage of the austral Sebastes; (5) the existence of a third evolutionary lineage with high levels of genetic divergence, particularly abundant in the south-western Atlantic, which may be recognized as a third austral species of Sebastes.  相似文献   

11.
Isofocusing and immunoblotting of reduced serum samples identify the common haptoglobin alpha-chain variants 1S, 1F, 2FS, 2SS, 2FF, 3, as well as several rare alpha- and beta-chain variants. The gene frequencies found in 6,668 unrelated persons involved in Norwegian paternity cases were: HP*1S: 0.22, HP*1F: 0.16, HP*2FS: 0.58, HP*2SS: 0.04, HP*2FF: 0.004, HP*3: 0.0004, other HP* alpha variants: 0.0004, HP* beta variants: 0.0008. The corresponding gene frequencies in 153 unrelated Norwegian Saamis (Lapps) were: HP*1S: 0.19, HP*1F: 0.07, HP*2FS: 0.70, HP*2SS: 0.04. Norwegians and Norwegian Saamis differed both in phenotype and allele distribution. An earlier Norwegian population study has shown a lower HP*1 frequency in the north than in the south. This regional difference in haptoglobin gene distribution was reflected in the present material as a lower 1F frequency, indicating a Saamish influence in northern Norway. Furthermore, the relatively low 2FF frequency in the north coincides with the lack of observed 2FF genes in the Saamish population. Non-Scandinavians involved in Norwegian paternity cases did not differ from the rest of the material. A review of published haptoglobin gene frequencies shows the 1F frequency to be a good indicator of ethnic origin, and that 2FF and 2SS frequency determinations may also be valuable in genetic population studies.  相似文献   

12.
This paper presents data on the distribution of 3 amplified fragment length polymorphisms (D1S80, APOB, and YNZ22) in 5 populations of Central India. Using the polymerase chain reaction technique, 3 caste (Brahmin, Khatri, and Dhimer) and 2 tribal (Gond and Baiga) populations were studied for the 3 loci. The allelic variations observed in the caste populations are compatible with those of many Caucasian populations, but the caste populations showed significant overall and interpopulation variability within the region. D1S80 allele *24 varied from 32% (Dhimers) to 42% (Brahmins). Allele *18 was not observed in Baiga tribal populations, but in caste populations it varied from 11% (Dhimers) to 24% (Brahmins). Both tribal populations showed higher frequencies of allele *31 (17%-18%). For APOB, caste populations again showed bimodal distribution of alleles *35 and *37, but in tribal populations higher allele numbers (*47, *49) were also frequent. For YNZ22, extensive variation was observed for all populations studied. Allele *4 was the most common in caste populations, while alleles *2, *7, and *10 were prominent in tribal populations. The level of gene differentiation is not very high for the 3 systems studied in the 5 populations. Overall, allele frequency distribution, heterozygosity, and genetic diversity analysis show that the genetic diversity observed is socially and geographically structured.  相似文献   

13.
Genetic variation in the major histocompatibility complex (MHC) class IIB was tested in Japanese flounder (Paralichthys olivaceus) for survival after challenge with bacterial infection. The material consisted of 6000 Japanese flounder from 60 families challenged with Vibrio anguillarum, which causes significantly different mortality in flounder families. Five individuals from each of six high-resistance (HR) and six low-resistance (LR) families were screened for their MHC class IIB genotypes using sequence analysis. High polymorphism of MHC IIB gene and at least three loci were discovered in Japanese flounder and the rate of d(N) occurred at a significantly higher frequency than that of d(S) in PBR. Among 60 individuals, 76 alleles were discovered and 15 alleles were used to study associations between alleles and resistance to disease. We found highly significant associations between resistance towards infectious disease caused by V. anguillarum and MHC class IIB polymorphism in Japanese flounder. Some alleles appeared in both HR and LR families, while some alleles were only discovered in HR or LR families. One allele, Paol-DAB*4301, was significantly more prevalent in HR families than in LR families (P=0.023). Paol-DAB*0601, Paol-DAB*0801, Paol-DAB*2001, Paol-DAB*3803 were discovered in two HR families with high frequency. One allele, Paol-DAB*1601, was discovered in three LR families. The steady heredity of MHC class IIB alleles was observed, and the family having Paol-DAB*4301 alleles was confirmed with higher resistance to V. anguillarum. This study confirmed the association between alleles of MHC class IIB gene and disease resistance, and also detected some alleles which might be correlated with high bacterial infection resistance. The disease resistance-related MHC markers could be used for molecular marker-assisted selective breeding in the flounder.  相似文献   

14.
Loss of genetic variation from genetic drift during population bottlenecks has been shown for many species. Red deer (Cervus elaphus) may have been exposed to bottlenecks due to founder events during postglacial colonisation in the early Holocene and during known population reductions in the eighteenth and nineteenth centuries. In this study, we assess loss of genetic variation in Scandinavian red deer due to potential bottlenecks by comparing microsatellite (n = 14) and mitochondrial DNA variation in the Norwegian and Swedish populations with the Scottish, Lithuanian and Hungarian populations. Bottlenecks are also assessed from the M ratio of populations, heterozygosity excess and from hierarchical Bayesian analyses of their demographic history. Strong genetic drift and differentiation was identified in both Scandinavian populations. Microsatellite variation was lower in both Scandinavian populations compared with the other European populations and mitochondrial DNA variation was especially low in the Swedish population where only one unique haplotype was observed. Loss of microsatellite alleles was demonstrated by low M ratios in all populations except the Hungarian. M ratios’ were especially low in the Scandinavian populations, indicating additional or more severe bottlenecks. Heterozygosity excess compared with the expectation from the number of observed microsatellite alleles suggested a recent bottleneck of low severity in the Norwegian population. Hierarchical Bayesian coalescent analyses consistently yielded estimates of a large ancestral and a small current population size in all investigated European populations and suggested the onset of population decline to be between 5,000 and 10,000 years ago, which coincide well with postglacial colonisation.  相似文献   

15.
Sporophytic self-incompatibility (SSI) was studied in 11 British Senecio squalidus populations to quantify mating system variation and determine how its recent colonization of the United Kingdom has influenced its mating behavior. S allele number, frequency, and dominance interactions in populations were assessed using full diallels of controlled pollinations. A mean of 5.1 S alleles per population was observed, and no population contained more than six S alleles. Numbers of S alleles within populations of S. squalidus declined with increasing distance from the center of its introduction (Oxford). Cross-classification of S alleles allowed an estimate of approximately seven and no more than 11 S alleles for the entire British S. squalidus population. The low number of S alleles observed in British S. squalidus compared to other SI species is consistent with the population bottleneck associated with S. squalidus' introduction to the Oxford Botanic Garden and subsequent colonization of Britain. Extensive S allele dominance interactions were observed to be a feature of the S. squalidus SSI system and may represent an adaptive response to improve limited mate availability imposed by the presence of so few S alleles. Multilocus allozyme genotypes were also identified for individuals in all populations and geographic patterns of S locus and allozyme loci variation investigated. Less interpopulation structure was observed for the S locus than for allozyme diversity--a finding indicative of the effects of negative frequency-dependent selection at the S locus maintaining equal S phenotypes within populations and enhancing effective migration between populations.  相似文献   

16.
PI and TF subtypes were studied in a sample of 137 individuals of the Chueta population. In addition to the PI*M alleles, PI*S, PI*Z, and PI*F were observed in the PI system. In the TF system no TF*B or TF*D alleles were found. PI results were compared with those of some Jewish and non-Jewish populations. The relatively high frequency of PI*S is indicative of a substantial Spanish influence. There are no previous data available on TF*C subtypes in Jews. The very low TF*C3 frequency in Chuetas (lower than in Spain) indicates that this allele may be extremely rare or absent in other Jewish populations.  相似文献   

17.
The population structure of the black rockfish, Sebastes inermis (Sebastidae), was estimated using 10 microsatellite loci developed for S. schlegeli on samples of 174 individuals collected from three wild and three hatchery populations in Korea. Reduced genetic variation was detected in hatchery strains [overall number of alleles (N(A)) = 8.07; allelic richness (A(R)) = 7.37; observed heterozygosity (H(O)) = 0.641] compared with the wild samples (overall N(A) = 8.43; A(R) = 7.83; H(O) = 0.670), but the difference was not significant. Genetic differentiation among the populations was significant (overall F(ST) = 0.0237, P < 0.05). Pairwise F(ST) tests, neighbor-joining tree, and principal component analyses showed significant genetic heterogeneity among the hatchery strains and between wild and hatchery strains, but not among the wild populations, indicating high levels of gene flow along the southern coast of Korea, even though the black rockfish is a benthic, non-migratory marine species. Genetic differentiation among the hatchery strains could reflect genetic drift due to intensive breeding practices. Thus, in the interests of optimal resource management, genetic variation should be monitored and inbreeding controlled within stocks in commercial breeding programs. Information on genetic population structure based on cross-species microsatellite markers can aid in the proper management of S. inermis populations.  相似文献   

18.
This study examined the seasonal use of rocky intertidal areas by young-of-the-year (YOY) Sebastes spp. at three locations in northern California, 2003 to 2005. Six species of Sebastes were noted during the study with black rockfish Sebastes melanops comprising >99% of the total number sampled. Sebastes melanops were noted in rocky intertidal areas from May to August with peak abundances occurring in May or June. Variation in recruitment and feeding was evident among years. Diet analysis, using the index of relative importance (% I RI) and the modified index (% I M), showed that YOY S. melanops and Sebastes mystinus consumed a variety of prey items with harpacticoid copepods and gammaridean amphipods being the dominant prey categories. The rocky intertidal appears to serve as an important habitat for YOY S. melanops in northern California.  相似文献   

19.
Five species of sand eels (Ammodytidae) are regularly found in the north-east Atlantic. Some of these species (i.e. Ammodytes tobianus L. and A. marinus Raitt) are difficult to identify by morphological criteria. The aims of the study reported were (a) to reveal unambiguous genetic traits for species classification and (b) to study possible population structure of the more common species in Norwegian waters. In total more than 900 specimens were analysed for inter- and intraspecific allozyme variation. Reference samples were obtained from Scotland and Denmark. By combining the patterns at different loci, all five species could be unambiguously defined. In Norwegian waters A. marinus was found together with minor numbers of Hyperoplus lanceolatus (Le Sauvage). As expected, Gymnammodytes semisquamatus (Jourdain) and H. immaculatus (Corbin) were not found, but not finding A. tobianus in these waters was unexpected. Distribution of alleles at three polymorphic loci did not indicate any structure of A. marinus in Norwegian waters.  相似文献   

20.
Here we report development and characterization of seven polymorphic loci derived from grass rockfish (Sebastes rastrelliger) genomic DNA phagemid libraries enriched for microsatellite motifs. Within grass rockfish, average allelic diversity was 11.3 alleles per locus and average heterozygosity was 0.73. The seven loci also were surveyed in 10 related species of Sebastes, where allelic diversity ranged from highly polymorphic to monomorphic. Deviations from Hardy–Weinberg were nonsignificant in all but one species/locus combination suggesting low occurrence of null alleles. Significant linkage disequilibrium was detected among three loci, but these events were limited to a single species in each case.  相似文献   

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