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  • Springer  (4)
  • Alfred Wegener Institute for Polar and Marine Research
  • 1995-1999
  • 1990-1994  (4)
  • 1994  (4)
Document type
Publisher
  • Springer  (4)
  • Alfred Wegener Institute for Polar and Marine Research
Years
  • 1995-1999
  • 1990-1994  (4)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 94 (1994), S. 295-298 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In lymphocyte cultures, the number of aneuploid cell nuclei increases with proband age mainly because of the loss of sex chromosomes. Since one possible cause of aneuploidy in cell nuclei is chromosomal lag at anaphase, with subsequent chromosome loss via micronucleus formation, we scored 5000 interphase nuclei from ten female and ten male probands for associated micronuclei. Whereas, in young (〈 10 years) probands, an average of 0.15% interphase nuclei exhibited micronuclei, the frequency rose to 0.46% in older probands (〉 70 years). In situ hybridizations with X-specific and Y-specific DNA probes were carried out, and the signal distribution in ten nuclei with associated micronuclei was documented for each donor. Our results indicate that the exclusion of sex chromosomes into micronuclei doubles during a human life, from 11% in young probands to 20% in old donors.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 93 (1994), S. 421-423 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Nonradioactive in situ hybridization with an α-satellite DNA probe specific for chromosome 18 was performed on human interphase sperm nuclei to detect the frequency of sperm cells disomic for chromosome 18. A total of 16127 sperm heads from eight healthy donors, aged 23–57 years, was investigated, and a minimum of 2000 sperm nuclei per proband was analyzed. The disomy rate ranged from 0.25% to 0.5%, with an average of 0.36%. This frequency does not differ significantly from that determined for other chromosomes.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In situ hybridizations were performed on mature human sperm cells with biotin-labeled α-satellite DNA probes specific for chromosomes 3, 7, 10, 11, 17, and X in order to reveal the disomy rate for each of these chromosomes. A total of 76 253 sperm nuclei from seven healthy probands aged 23–57 years were analyzed. An average of 12 000 sperm nuclei (at least 1500 per donor) showing hybridization were scored with each probe. The disomy rate as indicated by two distinct hybridization signals turned out to be similar for all chromosomes, ranging from 0.31% to 0.34%. There were no significant interindividual differences and no age correlation in the frequency of disomic sperm cells between the donors.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-3297
    Keywords: Poeciliid fish ; male size polymorphism ; reproductive success
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The male-polymorphic poeciliid fish,Limia perugiae, a small teleostean endemic to the southeast of the Caribbean island Hispañola, consists of three male size morphs with uniform females. Large males differentiate at a size varying between 25 and 38 mm; intermediate males, between 21 and 25 mm. Under competition, large males exhibit an elaborate courship display, whereas small males show only a sneak-chase behavior. Intermediate males adapt their tactics to the respective competitors. However, all male morphs can switch from courtship display to sneak-chase behavior. In large mating groups with four males of different size and five or six virgin females, large dominant α-males as well as small subordinate δ-males did not produce any offspring. Unexpectedly, all progeny were sired exclusively by the intemediate subordinate β- and γ-males. Breeding experiments with the three male morphs can best be explained by a model of Y-linked genes for small and large size which are both suspended by the activity of an autosomal recessive repressor responsible for the development of intermediate males. The dominant allele of the recessive repressor, in either its homoorits heteozygous state, activates the Y-chromosomal genes for large or small size, respectively. Accordingly, intermediate males may produce male offspring of all size classes, depending on the presence of either the Y-linked gene or the autosomal repressor.
    Type of Medium: Electronic Resource
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