1. Class Discussion Syphilis tree papers Your phylogenetic tree papers

2. Mutation/selection examples involving change in protein shape

3. Mc1r gene in Rock Mice Dark/light color varies by location Nachman et al., 2003, PNAS, 100: 5268 Kaufman, 1974 Conspicuous mice captured more frequently than cryptic mice Unusual color for the species

6. Mc1r gene in Rock Mice Nachman et al., 2003, PNAS, 100: 5268 Mc1rsome other gene “Different molecular solutions to arrive at the same phenotype in similar environments”

7. Mc1r gene in Beach Mice Steiner et al., Molecular Biology and Evolution, 26:35-45. Unusual color for the species

8. Experimental steps... 1. Documented phenotypic convergence in Gulf coast and Atlantic coast subspecies 2. Determined relationships among Gulf coast and Atlantic coast subspecies compared with inland mice 3.Sequenced the Mc1r coding region in all mice It was already demonstrated that in some beach mice, a point mutation in gene sequence changes Arg  Cys, which alters both ligand binding and receptor-signaling potentials consistent with light pigmentation I.e., Change in protein shape Steiner et al., Molecular Biology and Evolution, 26:35-45.

9. Beach mouse phylogeny mtDNA sequences + snp’s Light color arose > 1 time Steiner et al., Molecular Biology and Evolution, 26:35-45.

10. Mc1r gene tree mtDNA sequences + snp’s  A point mutation in gene sequence changes Arg  Cys Other light colored mice (color not due to same mutation) Steiner et al., Molecular Biology and Evolution, 26:35-45. “Different molecular solutions to arrive at the same phenotype in similar environments”

11. We’ve seen this convergence in phenotype from different genetic mechanisms before… e.g., convergent loss of pigment in cave fish populations is caused by independently derived mutations that prevents the Oca2 gene from producing a functional protein (LOF mutations) Protas et al., 2006, Nature Genetics

12. Mutation examples involving switches

13. What Darwin never knew (switches) video http://www.pbs.org/wgbh/nova/evolution/d arwin-never-knew.htmlhttp://www.pbs.org/wgbh/nova/evolution/d arwin-never-knew.html Watch 1:44:00 to 1:49:15