Squirrel Genetics University of Sheffield

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Squirrel Genetics(University of Sheffield)

• Melissa Gunn, Dave Coltman, Jon Slate, Andrew
  Leviston

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Determination of paternity

• Development of paternal lineage/relatedness
  matrix enables
• Determination of multiple paternity
• Analysis of inbreeding (present or absent)
• Estimates of Ne/N
• Analysis of population substructure
• Re-estimates of maternal effects, heritability
  using animal model
• And probably lots more...

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Step 1 Isolate microsatellites

• 6/13 working so far (Coreys clones)

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Find more microsatellites

• Get more sequences (aim for 20 polymorphic loci
  for paternity analysis) - make more clones
• Can use closely related species primers
• Currently trying Eurasian red squirrel primers

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Step 2 Use microsatellites!

• Using microsats, obtain 20-locus genotype for
  each individual
• Assign paternity based on microsats (CERVUS), or
  relatedness (sib-groups)
• Reconstruct pedigree from known mothers, assigned
  fathers
• Determine multiple paternity
• Is it correlated with differential survival of
  offspring?
• Is it correlated with food availability?

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Inbreeding?

• Determine if inbreeding occurs
• Estimate inbreeding coefficient (F)
• Is there correlation between F and reproductive
  success/growth rate/weight at weaning etc?
• Does inbreeding reduce phenotypic plasticity?

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Population Structure

• Is there genetic flow between all grids (i.e.
  metapopulation)?
• Is there population structuring?
• E.g. Does road stop gene flow?
• Estimate effective population size Ne

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Heritability Plasticity

• Using reconstructed pedigree, estimate
  heritability of traits (animal model)
• Maternal effects can also be re-estimated using
  full pedigree
• Phenotypic plasticity - between-year reaction
  norm measurements
• Determination of plasticity versus genetic
  alterations in response to selection

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Correlations

• Is survival to breeding age and/or lifetime
  reproductive success correlated with
  microsatellite heterozygosity?
• Are any loci associated with quantitative traits?
  --gt eventually could lead to mapping, with
  sufficient loci.
• Develop many markers with this aim in view

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Grant objectives

• Test that the means and plasticities of
  reproductive traits show sig. VA
• Test for negative correlations between trait
  means and plasticities which may constrain
  selection
• Test for positive covariance between maternal and
  direct genetic effects on reproductive traits
• Test that selection gradients vary temporally,
  but overall favour earlier parturition, stable
  litter size and maternal investment
• Test that increased food availability increases
  selection intensity on parturition date and
  offspring growth rate, while increasing potential
  response to selection by reducing individual
  environmental variance, decoupling the influence
  of maternal effects