1

Some stories about evolution

Wen-Ping Hsiehwphsieh@stat.nthu.edu.tw

Institute of StatisticsNational Tsing Hua University

Sep. 6, 2012

2

Outline

• Introduction to genetics• Genetic polymorphisms• Y-chromosome Adam and Mitochondria Eve• Human genome diversity

3

A Quick Introduction to Genetics

• DNA->RNA->Protein• Recombination• Mutation• Polymorphism

4

Source: Wikipedia

5http://www.accessexcellence.org/RC/VL/GG/central.php

6

Recombination Rate• There are only a few

crossover events occurred to each human chromosome in each meiosis.

• Recombination rate is higher between two close loci.

• Recombination rate is not consistent across chromosomes.

7

DNA Polymorphisms

• Single Nucleotide Polymorphism (SNP)• Microsatellites or Short Tandem Repeats (STR)• Insertion and deletion

8

Fossil Evidence of Human Evolution

9

Study of Blood Groups

• Blood type ABO• Different allele frequency across populations

Region A B O

Europe 27 8 65

British 25 8 67

Italian 20 7 73

Basques 23 2 75

East Asian 20 19 61

African 18 13 69

Indigenous American

1.7 0.3 98

Indigenous Australian

22 2 76

10

Classification of Populations

• With polymorphisms of ABO, RH and MN blood types, scientists can easily distinguish populations of the five continents. (The study of William Boyd)

• When we count in more features, almost all populations can be distinguished. That is, people live in Taipei can be genetically different from people in Taichung if we consider enough numbers of genetic features.

11

適者生存 or 幸者生存• Sickle Cell Anemia and Malaria defense– Natural selection

• O blood type of native American– Founder's effect– Natural selection: Syphilis epidemics

• Neutral genes

12

Forces of Evolution

• Mutation• Selection• Random drift• Migration

13

Genetic Distances

• How different are two individuals?– Difference between parents and children– Difference between grandparents and

grandchildren– Difference between any two unrelated persons.

• How different are two populations?

14

Genetic Distance among Five Continents

• The genetic distance was calculated from 100 genes for 15 Groups (three groups in each continent).

非洲 大洋洲 美洲 歐洲大洋洲 24.7

美洲 22.6 14.6

歐洲 16.6 13.5 9.5

亞洲 20.6 10.0 8.7 9.7

15

Phylogeny Tree

亞洲 美洲 歐洲 大洋洲 非洲

16

Y chromosome and Mitochondria

• Y chromosome can be traced to back to one man in Africa. That specific male is called the Scientific Adam.

• Both men and women carry mitochondria but only Moms pass it along. Hence, all our mitochondria can be traced to one single woman in Africa and she is called the Scientific Eve.

• Both appeared at around 144,000 years ago.• Haplogroups

17

Recent Viewpoint

Meet the Denisovans, indigenous Australia's Siberian kin Source: The Australian

18

19

How to Construct Phylogeny Tree

• Distance-based– Neighbor-joinning– UPGMA

• Maximum parsimony

20

Evolutionary History of Human

• DNA consists more information than fossils.• The rules of DNA change is a lot more simpler

than the metrics measured from fossils.

22

European Haplogroups of mtDNA

West Britain and Scandinaviahttp://freepages.genealogy.rootsweb.ancestry.com/~jswdna/haplogroupn.gif

23

European Haplogroups of mtDNA

Central and Eastern Europe, France, England

24

European Haplogroups of mtDNA

All around Europe

25

European Haplogroups of mtDNA

Northern Scandinavia, Saami

26

European Haplogroups of mtDNA

Eastern Baltic Sea, Ireland and the west of Britain

27

European Haplogroups of mtDNA

Ötzi the Iceman, Northern Italy, Around the Mediterranean32% of people with Ashkenazi Jewish ancestry

28

European Haplogroups of mtDNA

Mediterranean, Greece, Italy/Sardinia and SpainIreland, England-Wales, Scotland

29

The Genographic Project

30

Interactive Trail for the Journey of Mankind

http://www.bradshawfoundation.com/journey/

31

Migration of Austronesian ( 南島語系 )

Source: Wiki

32

Inference with Y chromosome

33

Other Side Stories

• Y-chromosomal Aaron– Haplogroup J-P58 consist of more than 50% of

Kohanim. It infers the most recent common ancestor living around 3200(± 1100) years ago.

– Haplogroup J-M410 consist of around 14% of Kohanim. It infers the most recent common ancestor living around 4200(± 1300) years ago.

• mtDNA and Y chromosome in Venezuela

34

Conclusion

• 統計是遺傳研究不可或缺的一部份• 遺傳則是統計研究裡面充滿想像與驚奇的旅程

35

References

• Geni, Popoli e Lingue ( 追蹤亞當夏娃 ) by Luigi Luca Cavalli-Sforza (2003)

• The journey of man: a genetic odyssey. Spencer Wells. (2002)

• The seven daughters of Eve ( 夏娃的七個女兒 ). Bryan Sykes. (2001)• National Geographic: The human family treehttp://topdocumentaryfilms.com/human-family-tree/