Lab 6. Overview

1. Lab 6. Overview • Instructor collects lab. 5 write up and checks pre-labs. in lab notebook • Discussion of microbial spp. rich. write up. • Hardy-Weinberg & Other Background. • Set up gels, examine blood smear slides, load samples, begin electrophoresis & then begin Simbiotic simulation • Compile electrophoresis data as a class. • finish Simbiotic simulation & in-class exercise • Examine plant cultures. • Discuss independent project & typed Lab. 6 write up due next week with instructor.

2. Modeling Evolutionary Change SIMPLE SITUATION = NO EVOLUTION • no mutation • no gene flow • no genetic drift • no assortative mating • no natural selection

3. Hardy-Weinberg • Hardy-Weinberg Theorem = predicts genotype frequencies (based on allele frequencies) in a population when it is NOT evolving. Allele Frequency Abbreviations p=frequency of A in the pop. q=frequency of a in the pop. [ % of A allele + % of a allele = 100% ] p + q = 1

4. Hardy-Weinberg • Hardy-Weinberg Theorem= predicts genotype frequencies (based on allele frequencies) in a population when it is NOT evolving. Hardy-Weinberg Equation(s) p2 =frequency of AA in the pop. 2pq =frequency of Aa in the pop. q2 =frequency of aa in the pop.

5. Is a Pop. at Hardy-Weinberg? • Pop. of 100 with 20AA, 20Aa, 60aa • Step 1–calculate the allele frequencies For 20AA, 20Aa, 60aa then freq. A = 0.30 = p freq. a = 0.70 = q • Step 2–plug into H.-W. equations p2 = (0.30)(0.30) = 0.09 2pq = 2(0.30)(0.70) = 0.42 q2 = (0.70)(0.70) = 0.49

6. Is a Pop. at Hardy-Weinberg? • Pop. of 100 with 20AA, 20Aa, 60aa • Step 3– multiply freqs. by pop. size p2 = 0.09100(0.09) = 9 AA individ. expected 2pq = 0.42100(0.42) = 42 Aa ind. expected q2 = 0.49  100(0.49) = 49 aa ind. expected • Step 4– compare observed and expected individuals (2 statistical test) 20AA, 20Aa, 60aa  9AA, 42Aa, 49aa

7. Electrophoresis

8. Human Variation, Approx. Circa 1491 • Humans do exhibit substantial genetic variation, and some of it is geographically patterned, but none diagnostically coincides with “races.”

9. Human Variation, Approx. Circa 1491 Allele frequencies vary regionally, so why wouldn’t this be enough to identify “biological” races?

10. Human Races • Race (biological definition) – distinct group of individuals of the same species sharing one or more constant genetic features that distinguish them from others within the species. Rarely used. [= No human biological races.] • Race (dictionary definition) – a family, tribe, group, or nation descended from the same individual or having unity of descent. [?] • Human Race (sociological definition) – a socially recognized group assumed to reflect ancestry; members are recognized based on certain physical and/or ancestry characteristics (e.g., skin color; having one ancestor categorized as a member of a race). • Recognized races vary among cultures & historically.

11. Today’s Activity Reminders • READ the instructions () in the manual. • All the data from all the gels will be combined to form the data that all students will analyze for the exercise due in Lab 7. • Do not overpipette. (Don’t push plunger beyond “the stop.”) • Do not pierce the bottom of the gel well. • Do not use Kimwipes on microscope lenses. • The simulation provides a graph of allele frequencies showing BOTH alleles. • Obtain your unpaired X2-test P-value using the online site on the course website

12. Complete your in-class exercise, examine your cultures, and discuss ind. project ideas with the instructor before you leave.