Bio 321 F13 lecture 1 v2

of the 4 causal processes listed

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Unformatted text preview: a6on by mice –  if there is at least a par6al gene6c basis to the differences in levels of secreted defense chemicals, then alleles causing higher levels of secre6ons will increase in frequency in the popula6on •  this is the core process of ecological adapta6on – but does not alone mean that adapta6on will occur what could work against the poten6al adap6ve scenario in the previous slide? •  migra6on of beetles into the popula6on from popula6ons with lower average levels of defense chemicals •  gene6c drig if popula6on size too small –  poten6ally adap6ve alleles decreasing in frequency due to chance (sampling error) what could work against the poten6al adap6ve scenario in the previous slide? •  reduc6on of gene6c varia6on – decreases the rate of adap6ve evolu6on •  this can be caused by: –  gene6c drig –  natural selec6on – reduces gene6c varia6on by purifying for genotypes that increase defensive chemicals •  NEVERTHELESS – adapta6on may occur in spite of these factors going against it we will study the basis of that process in this course •  what areas are we going to cover? –  basic gene6cs •  genotypes, heredity (mostly in diploid, sexually reproducing organisms = best understood gene6c system) –  popula6on gene6cs •  dynamics of genotypes and allele frequencies within and between popula6ons –  quan6ta6ve gene6cs •  using phenotypic data and sta6s6cs to understand traits with complex gene6c underpinnings –  basic ecological/evolu6onary genomics and metagenomics •  new area with many applica6ons to ecological gene6cs and evolu6onary biology You need to know this previous slide = “central dogma” of molecular biology (term used by the oldsters in the field) •  DNA – one strand is read (3’- >5’) by the transcrip6onal apparatus –  this is the non- coding strand –  the coding strand is the complementary 5’ - 3’ straind •  the codons can be read from this strand •  the mRNA is an RNA version of this strand with Uracil instead of thymine •  ATG (on the DNA), AUG on the mRNA, encoding methionine, is the star6ng codon for most protein- coding mRNAs –  used as a template to make a complementary RNA copy = ,RNA •  this will have the sequence of the complementary DNA stra...
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