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.

SIMPLE SITUATION = NO EVOLUTION

no mutation

no gene flow

no genetic drift

no assortative mating

no natural selection

Modeling Evolutionary Change

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

Hardy-WeinbergHardy-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.

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

Is a Pop. at Hardy-Weinberg?Pop. of 100 with 20AA, 20Aa, 60aa

Step 3– multiply freqs. by pop. sizep2 = 0.09100(0.09) = 9 AA individ. expected

2pq = 0.42100(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

Electrophoresis

Human Variation, Approx. Circa 1491 Humans do exhibit substantial genetic variation, and

some of it is geographically patterned, but none diagnostically coincides with “races.”

Human Variation, Approx. Circa 1491

Allele frequencies vary regionally, so why wouldn’t this be enough to identify “biological” races?

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.

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