Lab 5. Overview  Instructor collects lab.4 write up and checks pre-labs. in lab notebook  Discussion of graded plant species richness write up.  Basic Genetics Overview.  Microevolutionary Processes Overview.  Evolution simulation  Complete and turn in in-class exercise  Simulation discussion & questions (discuss graphs & exercise due in Lab 6)  C-fern and Arabidopsis culturing exercise

Genetics Overview  Genes (DNA) in cells direct cell activities.  Most cells have TWO copies of every kind of gene. One copy from each parent. (DIPLOID)  Sperm or egg have ONE copy of every kind of gene. (HAPLOID)

 The same gene can have different forms (Alleles, abbreviated e.g., B or b).  Dominant alleles affect the physical characteristics in any individuals with the allele. (capital, B)  Recessive alleles affect the physical characteristics ONLY in individuals with 2 copies of the allele. (lowercase, b)  Individual w/ same 2 alleles = homozygote. (e.g., bb or BB)  Individual w/ 2 diff. alleles = heterozygote. (e.g., Bb) Genetics Overview

Genotype & Allele Frequencies  Genotype Frequency – Answers “What proportion (percent) of individuals in this population has this genotype”? e.g., The frequency of Aa in the pop. is – See Appendix in lab manual.  Allele Frequency – Answers “What proportion (percent) of all alleles in this population is this specific allele”? e.g., The frequency of a in the pop. is 0.5. – See Appendix in lab manual.

Allele Frequency 12 beetles (individuals) 2 alleles per beetle = 24 alleles 17 green alleles 7 tan alleles 17  24 = = green allele frequency 7  24 = = tan allele frequency

Microevolutionary Processes  Mutation = new random genetic variation (new alleles). Change in the DNA (in a sex cell).  Genetic Drift = change in the genotype or allele freq. of a (small) pop. due to chance.  Natural Selection = differential reproduction (survival) if individuals due to the effect of particular genotypes in an environment.  Gene Flow = change in genotype or allele freq. in a population due to movement of individuals or gametes between populations  Non-Random Mating Inbreeding = increases homozygosity in pop. Outbreeding = increases heterozygosity in pop.

Microevolutionary Processes Over time… mutation increases variation (makes new alleles). genetic drift and natural selection usually decrease variation (lose alleles/fixation). gene flow and non-random mating usually redistribute variation (maintaining or decrease).

Simulation Reminders  Remember you are a hermaphrodite in this simulation. (Lucky you.)  You and a partner create two offspring, you both “die,” and then you both become the two offspring (1 each). You will always have only one genotype.  Don’t be a lazy mate. Move around to mate randomly.  You only need to flip the coin to determine which allele to give if you are heterozygous.

Figure. Hypothetical graphical example of the allele frequency of allele A in a population over 1000 generations. [A graph example for review after simulation data are tallied.]

Reminders for the Lab  READ the instructions (  ) in the manual  For culturing Ceratopteris spores be certain to maintain a sterile work environment. Fungal spore contamination can be a problem.  Be careful with the Bunsen burners and open flames. Do not set yourself on fire.  Do not roast the spreaders in the flame.  Do not put a hot spreader into the alcohol beaker.  Spread samples on the medium, not on the lid.