Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Genotype x environment  (1)
  • Inbreeding  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 80 (1990), S. 321-325 
    ISSN: 1432-2242
    Schlagwort(e): Heterosis ; Genetic distance ; Drosophila ; Inbreeding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The aim of the experiment was to determine if the estimated genetic distance between two populations could be used to predict the amount of heterosis that would occur when they were crossed. Eight lines of known relatedness to each other were produced by eight generations of sib mating and sub-lining. This produced lines that varied in coefficient of coancestry from zero to 0.78. Fourteen reciprocal crosses of these lines were used to measure heterosis for larval viability and adult fecundity. Gene frequencies at six polymorphic enzyme loci were used to estimate the genetic distances between lines, which were then compared with the known degrees of coancestry. The estimated genetic differences were poorly correlated with the known coancestry coefficients (r=0.4), possibly due to the small number of loci typed. Also genetic distances were only about 1/3 of what was expected. Selection acting on blocks of genes linked to the enzyme loci probably prevented the expected increase in homozygosity. Coancestry coefficient was correlated with heterosis (r=0.44–0.71). This level of correlation implied differences in heterosis among parent lines with the same level of coancestry. This variability is expected if a small number of loci explain most of the heterosis. The average level of heterosis was less than expected after eight generations of sib mating. This is most likely due to selection opposing the increase in homozygosity caused by inbreeding. The combination of these two imperfect correlations resulted in no significant correlation between genetic distance estimated from markers and heterosis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 77 (1989), S. 253-259 
    ISSN: 1432-2242
    Schlagwort(e): Heterosis ; Selection ; Drosophila ; Genotype x environment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Experiments were designed to examine whether heterosis would occur in crosses of Drosophila melanogaster populations adapted to 18 °C or 28 °C environments. Crosses were examined in parental environments, an intermediate environment (23 °C) and a mixed environment (alternating 18°/28°C). Parental populations did not show divergence for larval viability, cold shock or high temperature mortalities when tested in a common environment. However, the 28 °C population was less fecund than the 18 °C population, but had higher larval competitive ability and higher adult longevity. Heterosis for viability, cold shock mortality and high temperature mortality occurred in crosses between a population adapted to 18 °C and another adapted to 28 °C, but not in crosses between two populations adapted to the same temperature. The results suggest that, in the absence of drift, heterosis is expected in crosses between lines or populations with different histories of selection but not between lines with the same selection histories.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...