ATGTCATCA G ACGATGACTA

1. ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA In one of two offspring, a mutation occurs that changes a “G” to a “T” at some point in the DNA

2. ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

3. Descendants of both original two offspring now live mixed together and interbreeding as one big population ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

4. glacier (wall of ice) moves in, divides population in half now 2 populations, isolated from each other ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

5. bad luck strikes the “G”s.. each gets eaten by a tiger bad luck strikes the “T”s… each falls down a well ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

6. The two populations have become genetically different through isolation (physical separation) and random deaths; this is called genetic drift ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

7. Eventually, glacier melts into a river…  thousands of years later, what are the 2 possible ways you might find the offspring of these individuals distributed across the landscape? ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

8. If this species doesn’t swim, or move around much, DNA will show the “fingerprints” of past isolation  Each population might need to be conserved or managed separately, and not treated as one big population ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

9. If this species likes to swim, they will be all mixed-up; this is the effect of migration, which erases the genetic signature of past isolation ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

10. Now let’s go back to the beginning, and say that instead of 2 areas divided by a glacier, the environment was different ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

11. If the “T” mutation makes you more resistant to catching colds, but a little prone to over-heating… ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

12. If the “T” mutation makes you more resistant to catching colds, but a little prone to over-heating… ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

13. This time, the populations end up genetically differentiated because of natural selection (survival of the fittest) fittest: those who don’t overheat (G) fittest: those who don’t catch cold (T) ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA ATGTCATCATACGATGACTA ATGTCATCAGACGATGACTA

14. The combined effects of genetic drift and natural selection are constantly at work making isolated populations get different at the level of their DNA, and associated traits… may be slow (drift) or fast (selection) Migration and random interbreeding reverse these effects These forces control adaptation to local conditions, and ultimately this is how new species come into existence

15. Alaska: Innuit eskimo Ireland: freckly redhead Australia: aborigine

16. Ocean Conservation: Marine Protected Areas (MPAs) Since 1999, California has been establishing a system of MPAs to protect 11% of coast To be effective, migration must happen between MPAs Do larvae float between MPAs, keeping the populations genetically linked? (avoid inbreeding, local crashes) How do you space out MPAs? Where you put them? www.oceanconservancy.org

17. Computer models track how “virtual” tiny marine animals should migrate, by following ocean currents Animals should only migrate between locations in the same color family Cowen et al. 2006, Science

19. The Ultimate Vegetarians! My sea slugs can keep parts of the seaweed they eat ALIVEinside their bodies… - eaten seaweed performs photosynthesis, making sugar for the slug out of air & sunlight -- the slug never has to eat again!

20. Vegetarian sea slugs - closely related species often differ in how long their tiny, planktonic larvae swim in the ocean currents

21. Vegetarian sea slugs - closely related species often differ in how long their tiny, planktonic larvae swim in the ocean currents - use them to test computer model predictions: 1) do larvae that swim for longer actually go farther? 2) does migration really follow the ocean currents?

22. Some DNA positions show Jamaica is distinct from other populations  long history of isolation Jamaica NewP San Sal FL DNA from 44 specimens of the slug Elysia marcusi from four Caribbean populations, generated by high school students

23. Jamaica NewP San Sal FL At some sites, Florida is distinct  long history of isolation

24. Computer programs can draw a “family tree” from DNA sequences that may represent: 1) individuals in a family 2) populations within one species 3) different species within a group, like birds or insects great-grandma great uncle larry grandma grandpa his wife great aunt cass mom cousin kathy aunt chris uncle tom me tim chris

25. We can trace the history of populations and determine: - which populations are genetically unique, perhaps needing special protection - where is migration happening, or not happening DNA tree for 4 populations of one sea slug

26. New P FL San Sal Jamaica

28. Gulf Stream current appears to isolate Florida  FL Keys have genetically distinctive populations of most species