podcast.de
Anmeldung
Anmeldung Registrierung
Auto Hell Dunkel
Erweiterte Suche
  1. Startseite
  2. Podcasts
  3. Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 05/06 Podcast
  4. Evolution of genes related to temperature adaptation in Drosophila melanogaster as revealed by QTL and population genetics analyses
The fixation of beneficial variants leaves genomic footprints
characterized by a reduction of genetic variation at linked neutral
sites and strong, localized allele frequency differentiation among
subpopulations. In contrast, for phenotypic evolution the effect of
adaptation on the genes controlling the trait is little understood.
Theoretical work on polygenic selection suggests that fixations of
beneficial alleles (causing selective sweeps) are less likely than
small-to-moderate allele frequency shifts among subpopulations.
This thesis encompasses three projects in which we have
experimentally addressed the issue of selective sweeps vs. allele
frequency shifts in the context of polygenic adaptation. We studied
three X-linked QTL underlying variation in chill coma recovery time
(CCRT), a proxy for cold tolerance, in Drosophila melanogaster from
temperate (European) and tropical (African) environments. The
analysis of these QTL was performed by means of selective sweep
mapping and quantitative complementation tests coupled with
expression assays. While the results of the selective sweep mapping
approach identified a gene (CG4491) that is unlikely to be
affecting CCRT, quantitative and gene expression analyses revealed
two linked candidate genes (brk and CG1677) that appear to differ
in their evolutionary histories. We found that the difference in
expression of the gene brk between populations affects CCRT
variation. Cold tolerant flies from the temperate zone have a lower
expression of this gene than cold sensitive flies from the tropics.
We found that a likely cause of this difference is variation in a
cis-regulatory element in the brk 5’ enhancer region. Sequence
variants in this element exhibit moderate frequency differences
between populations from temperate and tropical environments,
forming two latitudinal clines: one from the equator to the north
and another one in opposite direction to the south. In contrast,
the other gene within the same QTL (CG1677), which is linked to
brk, showed no measurable effect on cold tolerance but is a likely
target of strong positive selection leading to a selective sweep in
the European population. These results are consistent with the
aforementioned theoretical predictions about footprints of
selection in polygenic adaptation. They are also proof of the
conceptual bias incurred when identifying candidate genes within a
QTL via selective sweep mapping, at least in naturally evolving
populations. The challenge for the evolutionary genetics community
in the coming years is to develop statistical tools that are as
powerful and robust as those already available to map selective
sweeps to identify sites in the genome where allele frequency
shifts have occurred due to adaptive evolution at the phenotypic
level. Finally, the last section of the results is a report of a
new population genetics dataset. It consists of a collection of 80
inbred lines from a natural D. melanogaster population in Sweden
and 19 full genome sequences derived from this sample. We hope this
material will provide us with further insight into the processes
underlying adaptation to novel and stressful environments.

Weitere Episoden

Signal transduction mechanisms and wiring specificity of bce-type antimicrobial peptide sensing and detoxification modules in firmicutes

Signal transduction mechanisms and wiring specificity of bce-type antimicrobial peptide sensing and detoxification modules in firmicutes

vor 10 Jahren
Classification and functional characterization of extracytoplasmic function (ECF) σ factors from planctomycetes and actinobacteria

Classification and functional characterization of extracytoplasmic function (ECF) σ factors from planctomycetes and actinobacteria

vor 10 Jahren
Diversity, molecular phylogeny, ecology and distribution of the genera Lactifluus and Lactarius (Russulales, Basidiomycota) in West Africa

Diversity, molecular phylogeny, ecology and distribution of the genera Lactifluus and Lactarius (Russulales, Basidiomycota) in West Africa

vor 11 Jahren
Breaking symmetry

Breaking symmetry

vor 11 Jahren
Untersuchung der gesteigerten Zytotoxizität von Trabectedin durch Hyperthermie in Tumorzellen

Untersuchung der gesteigerten Zytotoxizität von Trabectedin durch Hyperthermie in Tumorzellen

vor 11 Jahren
Alle Episoden anzeigen
In Podcasts werben
Schalte jetzt Werbung in Podcasts.
Episode melden

„Evolution of genes related to temperature adaptation in Drosophila melanogaster as revealed by QTL and population genetics analyses“

Worum geht es? Danach fragen wir noch nach dem Grund.

Abonnenten

Teilen

Mein Archiv

Deine Privatkopie der Folgen, die du nicht verlieren willst.

Podcast-Folgen verschwinden. Feeds werden auf die letzten Episoden gekürzt, Hoster räumen alte Dateien ab, Formate wechseln den Anbieter und lassen ihr Archiv zurück. Mit „Mein Archiv“ sichert podcast.de die Folgen deiner Podcasts für dich — angefangen bei den ältesten, denn die sind zuerst weg.

  • Deine gesicherten Folgen bleiben hörbar, auch wenn das Original offline geht.
  • Auch Folgen, die im heutigen Feed gar nicht mehr stehen — podcast.de kennt sie noch.
  • Herunterladen bleibt möglich, solange die Folge beim Podcaster liegt. Der zählt seine Abrufe wie bisher.
Startet bald

Sei beim Start von Mein Archiv dabei

Mein Archiv ist fast fertig. Trag dich ein, dann bekommst du eine E-Mail, sobald es losgeht – und bist von Anfang an dabei. Wir schreiben dir nur zum Start, keine Werbung, keine Weitergabe deiner Daten.

Du bekommst zuerst eine Bestätigungsmail. Abmelden geht jederzeit. Datenschutz