Sökning: "divergent selection"

Visar resultat 6 - 10 av 57 avhandlingar innehållade orden divergent selection.

  1. 6. Ecology and Evolution of Resistance to Herbivory : Trichome Production in Arabidopsis lyrata

    Författare :Geir Løe; Jon Ågren; Kari Lehtilä; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; Plant-animal interactions; herbivory; trichomes; plant resistance; plant defense; divergent selection; local adaptation; GLABROUS1; evolution; matrix population models; LTRE; Biologi; Biology; Biologi;

    Sammanfattning : In this thesis, I examine variation in occurrence and performance of glabrous and trichome-producing plants of the perennial herb Arabidopsis lyrata. I combine field studies and genetic analysis to (1) examine the function of trichomes as a resistance character in natural populations, (2) compare the magnitude of population differentiation in trichome-production and at putatively neutral marker loci, (3) examine the molecular genetic basis of trichome-production, and (4) quantify the effects of herbivore removal on population growth and relative performance of glabrous and trichome-producing plants. LÄS MER

  3. 7. Gene Expression in the Brains of Two Lines of Chicken Divergently Selected for High and Low Body Weight

    Författare :Sojeong Ka; Finn Hallböök; Tom Porter; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; chicken; juvenile body weight; divergent selection; gene expression; DNA microarray; quantitiative RT-PCR; hypothalamus; neural plasticity; melanocortin system; endogenous retrovirus; carnitine palmitoyltransferase-1b; Neurobiology; Neurobiologi; medicinsk utvecklings- och neurobiologi; Developmental Neurosciences;

    Sammanfattning : Artificial divergent selection of chickens for high and low body weight at 8 weeks of age has produced two lines: the high (HWS) and low (LWS) body weight chicken lines. In addition to the difference in body weight, the lines show extreme differences in feeding behaviour and body composition. LÄS MER

  4. 8. Genetic variation in natural populations: a modeller's perspective

    Författare :Marina Rafajlovic; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; coalescent process; site frequency spectrum; multiple paternity; dominant clone; divergent selection;

    Sammanfattning : Thanks to advances in genome sequencing, empirical patterns of within- and between-species genetic variation are readily available. By studying these patterns much has been learned about the evolutionary histories of species. But the causes and consequences of different evolutionary histories are still difficult to tell apart. LÄS MER

  5. 9. The evolutionary ecology of niche separation : Studies on the sympatric butterflies Leptidea sinapis and Leptidea reali

    Författare :Magne Friberg; Wiklund Christer; John N. Thompson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lepidoptera; ecological character displacement; reproductive isolation; species discrimination; habitat; host plant; life history; sexual selection; female choice; Biology; Biologi; zoologisk ekologi; Animal Ecology;

    Sammanfattning : Studies of ecology and evolution have become largely integrated, and increasing attention is paid to the role of ecology for speciation and post speciation divergence. In this thesis I have applied an in-depth approach studying the ecology of a butterfly species pair; the morphologically virtually identical sister-species, the Wood white (Leptidea sinapis) and Reál’s wood white (Leptidea reali). LÄS MER

  7. 10. Brain morphology and behaviour in the guppy (Poecilia reticulata) : Effects of plasticity and mosaic brain evolution

    Författare :Stephanie Fong; Niclas Kolm; Björn Rogell; Stephen Montgomery; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; brain plasticity; cognition; reversal learning; spatial learning; directed selection; mosaic brain; heritability; brain morphology; boldness; relative telencephalon size; inhibitory control; detour task; Poecilia reticulata; etologi; Ethology;

    Sammanfattning : Understanding how brains have evolved and subsequently culminated in the huge variation in brain morphology among contemporary vertebrate species has fascinated researchers for many decades. It has been recognized that brain morphology is both genetically and environmentally determined. LÄS MER