slide1 n.
Download
Skip this Video
Download Presentation
Introduction

Loading in 2 Seconds...

play fullscreen
1 / 11

Introduction - PowerPoint PPT Presentation


  • 47 Views
  • Uploaded on

North American populations of Entoleuca mammata are genetically more variable than populations in Europe. Introduction. What is E. mammata ?

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Introduction' - graceland


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

North American populations of Entoleuca mammata are genetically more variable than populations in Europe

introduction
Introduction
  • What is E. mammata?
  • A damaging pathogen in Populus tremuloides, P. grandidentata in North America, and Populus alba, P.trichocarpa, P.tremula and the hybrid aspen in Europe
  • Major cause of aspen death

http://www.glfc.cfs.nrcan.gc.ca/treedisease/photos/Pg%2052-c.JPG

locations
Locations
  • NA locations:
  • North-east, Great Lakes region, North-western prairies
  • Noticeably absent in Rocky mountains, Alaska (abundance of aspens?)
  • Thought to be restricted to NA
  • EU locations:
  • Noticed in France(1975)
  • Isolated regions in the French Alps
  • 2 races of P. tremula, mountains and plains
  • No serious outbreaks
  • Coexistance? Coevolution?
objective and hypothesis
Objective and Hypothesis
  • Objective: to investigate relationship btw NA and EU
  • Hypothesis:
  • 1) NA and EU are conspecific
  • 2) Fungus was introduced btw continents resulting in both founder and bottleneck effect
  • To prove:
  • 1) should have identical alleles and no phylogenetic grouping according to geographic origin.
  • 2) measure genetic variability btw continents
materials and methods
Materials and Methods
  • Samples from both EU and NA collected
  • 63 samples collected to analyze
  • Wood surface sterilized and incubated
  • Isolates incubated
  • Ascospore isolations
  • Most isolations of hyphae from canker margins

http://www.na.fs.fed.us/spfo/pubs/fidls/hypoxylon/hypox_fig1.jpg

http://www.forestpathology.org/hypoxylo.gif

hypothesis of conspecificity
Hypothesis of Conspecificity
  • Alleles determined by sequencing=
  • Several identical alleles
  • Consensus trees, phenograms, bootstrap programs, and calculations=
  • Lack of phlyogenetic grouping of alleles
  • Therefore species conspecific
direction of introduction
Direction of Introduction
  • Introduced continent = lower genetic diversity
  • Nei’s, Chao-estimates, rarefaction

curves

  • EU lower diversity than NA
  • NA had unique genotypes
  • EU had identical genotypes
  • Therefore,
  • NA→EU
testing introduction hypothesis
Testing introduction hypothesis
  • Measured genetic differentiation
  • Founder effect→ Fst and Gst calculated
  • High Fst= low gene flow
  • Low Fst= high gene flow (high differentiation)
  • Gst close to 0= variation within population
  • Gst close to = populations different
  • Results
  • Fst=0.193 (low)
  • Gst= 0.160 (low)
  • Therefore, high differentiation within population

http://www.umbc.edu/bioclass/biol100/powerpoints/lecture10/img032.jpg

bottleneck effect
Bottleneck effect?
  • Bottleneck effect
  • Population reduced by atleast 50%
  • New mutations in a small population
  • Should of produced unique alleles
  • Reduce NA and EU identical alleles
  • No unique EU alleles
  • Therefore, no bottleneck effect
  • Introduction effect favoured

http://www.uri.edu/artsci/bio/twombly/BIO113/images/drift2a.jpg

possible introduction events
Possible introduction events?
  • Wide variety of hosts
  • Carried by humans
  • Long-distance air dispersal
  • Insects and birds

http://www.rspb.org.uk/Images/great%20spotted%20woodpecker%20on%20tree%20stump%20180_tcm3-27242.jpg

http://www.canadianbiodiversity.mcgill.ca/english/species/insects/agromyzidae.jpg

summary
Summary
  • E. Mammata
  • Conspecific between NA and EU
  • Native to NA
  • Introduced to EU
  • Founder effect