BIOL3045 Lecture Notes - Lecture 6: Dna Methyltransferase, Epigenetics, Microevolution
3 Jul 2018
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Animal Ecological Physiology BIOL3045 460381099
Lecture 6: Adaptation.
• Further into adaptation. Example: Sticklebacks were found in uplifted lakes due to earthquake.
Salt water drained away and freshwater came in (this took 50 years). Freshwater fish don’t do as
well in salt water and each perform better in native environment; Stream and lake stickleback
could interbreed with each other, but don’t as they can’t handle the other environments. Fish
also grow better in their native environment.
Read: Skinner, M. K. Environmental epigenetics and a unified theory. Genome. Biol. Evol. 7.5, 1296.
• How are traditional genetics inadequate in explaining biological phenomena? Phenotypes
change much faster than genotypes. Genetically identical organisms can have different
phenotypes. Small percentage of genotypes have correlated genetic disease.
• Can epigenetic changes act across generations? Yes, DNA methylation patterns can be
maintained across generations. It can be a mechanism driving microevolution.
• How are epigenetics fundamentally different from traditional genetics in mediating
environmental influences? Epigenetics act on the phenotype directly, without change in the
nucleotide sequence. Genetics act by selection across generations, mutations and changes in
allele frequency. Changes transcription.
• What does the Unified Theory encompass? Epigenetics and genetics act in tandem. Epigenetic
marks can alter mutation rates and selection and thereby genotypic variation. Generics alter
epigenetics: evolution of developmental modifiers such as DNMT enzymes.
