Intraindividual Chromosomal Polymorphism in Green Sunfish (Lepomis cyanellus) as Evidence of Somatic Segregation

1966 ◽  
Vol 5 (5) ◽  
pp. 313-320 ◽  
Author(s):  
W. Beçak ◽  
M.L. Beçak ◽  
S. Ohno
1979 ◽  
Vol 31 (4) ◽  
pp. 312-323 ◽  
Author(s):  
Montserrat García ◽  
Rosa Miró ◽  
Montserrat Ponsá ◽  
J. Egozcue

Author(s):  
Elsie M. B. Sorensen

The detoxification capacity of the liver is well documented for a variety of substances including ethanol, organic pesticides, drugs, and metals. The piscean liver, although less enzymatically active than the mammalian counterpart (1), contains endoplasmic reticulum with an impressive repertoire of oxidizing, reducing, and conjugating abilities (2). Histopathologic changes are kncwn to occur in fish hepatocytes following in vivo exposure to arsenic (3); however, ultrastructural changes have not been reported. This study involved the morphometric analysis of intracellular changes in fish parynchymal hepatocytes and correlation with arsenic concentration in the liver.Green sunfish (Lepomis cyanellus, R.) were exposed to 0, 30, or 60 ppm arsenic (as sodium arsenate) at 20°C for 1, 2, or 3 week intervals before removal of livers for quantification of the arsenic burden (using neutron activation analysis) and morphometric analysis of ultrastructural alterations. Livers were cut into 1 mm cubes for fixation, dehydration, and embedding.


Author(s):  
E. M. B. Sorensen ◽  
R. R. Mitchell ◽  
L. L. Graham

Endemic freshwater teleosts were collected from a portion of the Navosota River drainage system which had been inadvertently contaminated with arsenic wastes from a firm manufacturing arsenical pesticides and herbicides. At the time of collection these fish were exposed to a concentration of 13.6 ppm arsenic in the water; levels ranged from 1.0 to 20.0 ppm during the four-month period prior. Scale annuli counts and prior water analyses indicated that these fish had been exposed for a lifetime. Neutron activation data showed that Lepomis cyanellus (green sunfish) had accumulated from 6.1 to 64.2 ppm arsenic in the liver, which is the major detoxification organ in arsenic poisoning. Examination of livers for ultrastructural changes revealed the presence of electron dense bodies and large numbers of autophagic vacuoles (AV) and necrotic bodies (NB) (1), as previously observed in this same species following laboratory exposures to sodium arsenate (2). In addition, abnormal lysosomes (AL), necrotic areas (NA), proliferated rough endoplasmic reticulum (RER), and fibrous bodies (FB) were observed. In order to assess whether the extent of these cellular changes was related to the concentration of arsenic in the liver, stereological measurements of the volume and surface densities of changes were compared with levels of arsenic in the livers of fish from both Municipal Lake and an area known to contain no detectable level of arsenic.


Genetics ◽  
1964 ◽  
Vol 49 (4) ◽  
pp. 669-687
Author(s):  
Harrison D Stalker

Genetics ◽  
2002 ◽  
Vol 160 (1) ◽  
pp. 247-256
Author(s):  
M Kauer ◽  
B Zangerl ◽  
D Dieringer ◽  
C Schlötterer

Abstract Levels of neutral variation are influenced by background selection and hitchhiking. The relative contribution of these evolutionary forces to the distribution of neutral variation is still the subject of ongoing debates. Using 133 microsatellites, we determined levels of variability on X chromosomes and autosomes in African and non-African D. melanogaster populations. In the ancestral African populations microsatellite variability was higher on X chromosomes than on autosomes. In non-African populations X-linked polymorphism is significantly more reduced than autosomal variation. In non-African populations we observed a significant positive correlation between X chromosomal polymorphism and recombination rate. These results are consistent with the interpretation that background selection shapes levels of neutral variability in the ancestral populations, while the pattern in derived populations is determined by multiple selective sweeps during the colonization process. Further research, however, is required to investigate the influence of inversion polymorphisms and unequal sex ratios.


1965 ◽  
Vol 16 (3) ◽  
pp. 845-850 ◽  
Author(s):  
Arthur L. McDonald ◽  
Norman W. Heimstra

Seven species of fish were studied in an attempt to determine interspecies differences in the amount and type of agonistic behavior shown. Fish in each species were paired and the frequency of attacks shown during a 5-min. observation session was recorded. An observation session was held for 16 pairs of fish of the same species on 5 consecutive days. It was found that bluegill showed the highest frequency of attacks, then green sunfish, largemouth bass, rainbow trout, black crappie, and yellow perch in that order. No attacks were recorded for walleyes during any of the observation sessions. Qualitative differences shown in agonistic behavior among the various species are also discussed.


1974 ◽  
Vol 49 (6) ◽  
pp. 413-424 ◽  
Author(s):  
TUTOMU HAGA ◽  
HIROSHI WATANABE ◽  
AKINORI UCHINO

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