Where do we come from?

1. Where do we come from?

2. Where do we come from? -Homo erectus evolved in Africa and spread to the rest of the world ~1-2 million years ago. What about the evolution of the modern humans? Two main hypothesis: 1. Multiregional evolution 2. Recent African origin

3. Human Genetics Mutations in human DNA are used to show relationships and evolutionary history. -The haploid human genome occupies a total of just over 3 billion DNA base pairs. -Human genome contains about 30,000 genes.

4. -Mitochondria are organelles living inside the cell -They are responsible for making ATP, the cell energy-coin What are Mitochondria?

5. Where do Mitochondria come from? phagocytosis - Originally from small bacteria swallowed by larger bacteria.

6. How do we know they evolved from bacteria? -They have there own circular genome, like bacteria -Double membrane: Original + Phagosome -Protein-synthesis machinery resembles bacteria - And more...

7. When cells divide, mitochondria are divided as well How are Mitochondria passed during fertilization? Both men and women possess mtDNA, but only women pass it on to their children. While female eggs contain lots of mitochondria, male sperm contains only a few, which are destroyed after fertilization.

8. Therefore, the mitochondria that we have are passed down from mother to children mtDNA

9. The human mitochondrial genome The rate at which mutations occur in nuclear DNA is extremely low (~only one in one thousand million will mutate at every cell division). In mitochondria, about twenty times as many mutations.

10. Chromosomes Vs. Mitochondrial genome 3 billion bp 16,500bp Inherited from both parents Inherited from the mother Error –checking mechanisms High mutation rate (10-4) Mutation rate: 1 in 1,000,000,000

11. The human mitochondrial genome ? ? ?

12. Mitochondrial D-loop (variable region) ATTCTAATTT AAACTATTCT CTGTTCTTTC ATGGGGAAGC AGATTTGGGT ACCACCCAAG TATTGACTCA CCCATCAACA ACCGCTATGT ATTTCGTACA TTACTGCCAG CCACCATGAA TATTGTACGG TACCATAAAT ACTTGACCAC CTGTAGTACA TAAAAACCCA ATCCACATCA AAACCCCCTC CCCATGCTTA CAAGCAAGTA CAGCAATCAA CCCTCAACTA TCACACATCA ACTGCAACTC CAAAGCCACC CCTCACCCAC TAGGATACCA ACAAACCTAC CCACCCTTAA CAGTACATAG TACATAAAGC CATTTACCGT ACATAGCACA TTACAGTCAA ATCCCTTCTC GTCCCCATGG ATGACCCCCC TCAGATAGGG GTCCCTTGAC - D-loop has high mutation rate

13. “Molecular clock” Mutation rate: 1 per 20,000 years (for mitochondrial variable region )

14. Example Gene sequence A: AGACGCCTATATA Gene sequence B: AGGCGCCTATATA Gene sequence C: AGACGCCTATTTA

15. Example B A C AGACGCCTATATA AGGCGCCTATATA AGACGCCTATTTA

16. Example AGGCGCCTATATA AGACGCCTATATA AGACGCCTATTTA B A C Sequence B is approximately 20,000 years older then sequence A and 40,000 years older then sequence C.

18. We can determine common ancestral mothers by changes in the sequence of the mitochondrial genome

19. African Eve or the Mitochondrial Eve The existence of the Mitochondrial Eve is NOT a theory; it is a mathematical fact Many researchers take the mitochondrial evidence as support for the "single-origin" or Out-of-Africa model

20. The migration of maternal clans

22. The Seven Daughters of Eve Xenia Ursula Helena Katrine Tara Velda Jasmine

23. Next week: Sequencing analysis PCR sequencing

24. Sequencing analysis Reference sequence (Helena): ATTCTAATTTAAACTATTCTCTGTTCTTTCATGGGGAAGCAGATTTGGGTACCACCCAAGTATTGACTCACCCATCAACAACCGCTATGTATTTCGTACATTACTGCCAGCCACCATGAATATTGTACGGTACCATAAATACTTGACCACCTGTAGTACATAAAAACCCAATCCACATCAAAACCCCCTCCCCATGCTTACAAGCAAGTACAGCAATCAACCCTCAACTATCACACATCAACTGCAACTCCAAAGCCACCCCTCACCCACTAGGATACCAACAAACCTACCCACCCTTAACAGTACATAGTACATAAAGCCATTTACCGTACATAGCACATTACAGTCAAATCCCTTCTCGTCCCCATGGATGACCCCCCTCAGATAGGG GTCCCTTGAC

25. THE END