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Schol Biol : Genetics. Schol Biol. Dr. Victoria Metcalf, Rm RFH046, x30628. Schol Question 2012. Prokaryotes vs. eukaryotes. Full genetic potential is never realised concomitantly

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Schol biol genetics
ScholBiol: Genetics


Dr. Victoria Metcalf, RmRFH046, x30628

Schol question 2012
Schol Question 2012

Schol biol genetics

Prokaryotes vs. eukaryotes

  • Full genetic potential is never realisedconcomitantly

  • Adapter molecules (tRNA) involved to bridge information transfer gap between mRNA and amino acids

Biology, Russell et al

Fig. 15-3, p. 305

Schol biol genetics

A natural laboratory

  • Polar organisms = ‘canaries in a coal mine’

  • What can we determine about the evolution of Antarctic marine animals? = PAST/PRESENT

  • What is their capacity to adapt to future change? (‘Health check’) = FUTURE



Schol biol genetics

Ocean Acidification





  • Relative proportions of the three inorganic forms of CO2 dissolved in seawater.

  • Green arrows indicate narrow oceanic range of pH at present

RS report 2005 (Figures courtesy Scott Doney, Woods Hole Oceanographic Institution)

RHS Wikimedia Commons

Where it happens
Where it happens

Wikimedia Commons

Schol biol genetics

Integrative biology

  • Assessing if there is decreased fitness of calcifying organisms due to ocean acidification

  • Predict that the effects of acidification are species dependent, and linked to location via variations in water temperature and food supply

Schol biol genetics

Granite Harbour

Schol biol genetics

Experimental setup

  • Sentinel Antarctic benthic bivalves (circum Antarctic)

  • Laternulaelliptica

  • Adamussiumcolbecki

  • pCO2levels of:

  • natural environment (430 μatm, pH 7.99)

  • predicted for 2100 (735 μatm, pH 7.78)

  • glacial levels (187 μatm, pH 8.32).

Schol biol genetics


  • Physiological parameters

  • Respiration (oxygen consumption)

  • Molecular parameters

  • Gene expression changes

    • Chitin synthase (shell structure)

    • HSP70 (stress)

  • Biochemical measurements

  • Carbonic anhydrase activity

Schol biol genetics

Gene expression studies – the basics

  • Genes within DNA are a code for proteins (proteins do the actual work in our bodies)

  • In cells, genes are copied into a message form (messenger RNA/mRNA) to then be used by the protein making factories (ribosomes)

  • The copying for any particular gene is switched on and off as required

  • Specific target pieces of genetic material can be copied and amplified using a technology called polymerase chain reaction or PCR for short

  • We use a special type of PCR to look at the genes actually being copied and therefore used at any one time is:

    • Reverse Transcription (RT)-PCR

    • Where mRNA is amplified via cDNAsynthesis

    • cDNA is a stable copy of mRNA (the message)

Schol biol genetics

Gene expression studies – functional genomics

  • qPCR (quantitative or real time PCR) is another special type of PCR

  • Used to look at the expression of particular genes (RT-qPCR) and assess how much message template was present (analysethis in real time in the machine)

  • Compare the amounts from different treatments (e.g. molluscs exposed to normal vs. low pH) and reference against the expression levels of one or more reference genes (these should remain stable no matter what)

Schol biol genetics

  • Upregulation of HSP70 expression indicating a stress at both low + high pH

  • Negative correlation between pH & chitin synthase expression (calcification gene)

Schol biol genetics

What else?

  • Temperature effects on Antarctic fish and fat saturation levels

  • The microbiome- humans, other animals