Charts, Graphs, & Diagrams > Evolution > Mitochondrial Eve and Y-chromosomal Adam Diagrams

Mitochondrial Eve and Y-chromosomal Adam Diagrams

These diagrams show how one line of mitochondria and one line of Y-chromosomes become widespread over time.

In our example, we have 8 original members of our population. Imagine that they are the only inhabitants of an island, if you like. We put them through several generations of random pairings and see how their genes are propagated over time. Eventually mitochondrial Eve and Y-chromosomal Adam for this tiny group are determined. The same principles apply to larger groups and the entire human race.

Here a few books that discuss the concept of mitochondrial Eve and Y-chromosomal Adam:

Wikipedia - that wonderful resource - has good entries on Mitochondrial Eve and Y-chromosomal Adam.

Please contact me if you have questions, comments, or suggestions about this page.

How to read the diagrams     Generations     Discussion     Condensed versions    

How to read the diagrams


Personal Characteristics

Each person is represented by the characteristics we want to look at enclosed in a black outline, like this:

1Bbbs

Here are the elements, in order:

As a mnemonic device, we use consonants B, C, D, and F to represent males and vowels A, E, I, and U for females.

Pairing up and producing new people.

Each new generation is created by the previous generation pairing up and producing offspring. In these simplified diagrams, every pairing produces two children, and altogether 4 boys and 4 girls are born in each generation. We represent one pairing and offspring combination in a blue box:

1Bbbs& 5aaAs
9BaAs 10BbAs

1 & 5 → boy 9 & boy 10

Previous generation persons 1 (male) and 5 (female) have paired up.
New generation persons 9 (male) and 10 (male) are produced.
A brief description of the pairing and offspring.

Note the inheritance rules shown here:

Note that we don't have any new mutations in these diagrams. The only genes present in generation 8 are ones that were present in generation 1.

However - this is the main point of the diagram - many genes that are present in generation 1 are not present in generation 8. Some are lost, the diagrams show how.

Generation 1: Persons 1-8

Our founding population. 4 men and 4 women, each with unique variations of mitochondrial DNA, X and Y chromosomes, and fingerprint.

1Bbbs   2Cccs   3Ddds   4Fffs   5aaAs   6eeEs   7iiIs   8uuUs

Now our population pairs up, each pair having two children

Generation 2: Persons 9-16

1Bbbs& 5aaAs
9BaAs 10BbAs

1 & 5 → boy 9 & boy 10

2Cccs& 6eeEs
11CcEs 12eeEs

2 & 6 → boy 11 & girl 12

3Ddds& 7iiIs
13idIs 14DdIs

3 & 7 → girl 13 & boy 14

4Fffs& 8UuUs
15ufUs 16uuUs

4 & 8 → girl 15 & girl 16

After 1 generation:

Generation 3: Persons 17-24

9BaAs& 12eeEs
17BeEs 18ieEs

9 & 12 → boy 17 & girl 18

10BbAs& 13idIs
19ibIs 20BdIs

10 & 13 → girl 19 & boy 20

11CcEs& 15ufUs
21ucUs 22ucUs

11 & 15 → girl 21 & girl 22

14DdIs& 16uuUs
23DuUs 24DdUs

14 & 16 → boy 23 & boy 24

After the next generation:

Generation 4: Persons 25-32

17BeEs& 19ibIs
25ieIs 26BeIs

17 & 19 → girl 25 & boy 26

20BdIs& 21ucUs
27ucUs 28udUs

20 & 21 → girl 27 & girl 28

23DuUs& 22ucUs
29DuUs 30DcUs

23 & 22 → boy 29 & boy 30

24DdUs& 18ieEs
31DdUs 32eeEs

24 & 18 → boy 31 & girl 32

Generation 5: Persons 33-40

26BeIs& 27ucUs
33ueUs 34ueUs

26 & 27 → girl 33 & girl 34

29DuUs& 28udUs
35DuUs 36DuUs

29 & 28 → boy 35 & boy 36

30DcUs& 32eeEs
37DcEs 38ecEs

30 & 32 → boy 37 & girl 38

31DdUs& 25ieIs
39ieIs 40DeIs

31 & 25 → girl 39 & boy 40

Generation 6: Persons 41-48

35DuUs& 38ecEs
41DuEs 42DcEs

35 & 38 → boy 41 & boy 42

36DuUs& 39ieIs
43DeIs 44iuIs

36 & 39 → boy 43 & girl 44

37DcEs& 33ueUs
45DcUs 46ucUs

37 & 33 → boy 45 & girl 46

40DeIs& 34ueUs
47ueUs 48ueUs

40 & 34 → girl 47 & girl 48

Generation 7: Persons 48-56

41DuEs& 44iuIs
49DuIs 50DuIs

41 & 44 → boy 49 & boy 50

43DeIs& 47ueUs
51DeUs 52ueUs

43 & 47 → boy 51 & girl 52

45DcUs& 48ueUs
53DeUs 54ucUs

45 & 48 → boy 53 & girl 54

42DcEs& 46ucUs
55ucUs 56ucUs

46 & 42 → girl 55 & girl 56

Generation 8: Persons 57-64

49DuIs& 52ueUs
57DeUs 58DeUs

49 & 52 → boy 57 & boy 58

50DuIs& 54ucUs
59DuUs 60ucUs

50 & 54 → boy 59 & girl 60

51DeUs& 55ucUs
61DeUs 62ucUs

51 & 55 → boy 61 & girl 62

53DeUs& 56ucUs
63ucUs 64ucUs

53 & 56 → girl 63 & girl 64

Discussion

I'm a chartmaker, not a geneticist, so I will stick to the highlights I wanted to show in the diagrams.

Although it was not the point of the diagrams, you can also see the effect of inbreeding in a small population. The total number of genes is much reduced over time. A recessive genetic defect that existed in the 1st generation would be unnoticed. However, if it survived to generation 8 it would be a serious problem because the chance that both parents possessed it would be high.

Condensed Version

Here we've removed all the pairing information and just show the new generations. You can't tell which children belong to which parents in this version, but you can still see how the presence of the mitochondrial genes and Y chromosome changes with each generation.

We've highlighted the eventual Eve and Adam to make it easier to track their genes across the generations.

Highlighted Mitochondrial Eve

Generation
1  1Bbbs   2Cccs   3Ddds   4Fffs   5aaAs   6eeEs   7iiIs   8uu U s 
2  9BaAs  10BbAs  11CcEs  12eeEs  13idIs  14DdIs  15uf U s  16uu U s 
3 17BeEs  18ieEs  19ibIs  20BdIs  21uc U s  22uc U s  23Du U s  24Dd U s 
4 25ieIs  26BeIs  27uc U s  28ud U s  29Du U s  30Dc U s  31Dd U s  32eeEs 
5 33ue U s  34ue U s  35Du U s  36Du U s  37DcEs  38ecEs  39ieIs  40DeIs 
6 41DuEs  42DcEs  43DeIs  44iuIs  45Dc U s  46uc U s  47ue U s  48ue U s 
7 49DuIs  50DuIs  51De U s  52ue U s  53De U s  54uc U s  55uc U s  56uc U s 
8 57De U s  58De U s  59Du U s  60uc U s  61De U s  62uc U s  63uc U s  64uc U s 

Highlighted Y-chromosomal Adam

Generation
1  1Bbbs   2Cccs   3 D dds   4Fffs   5aaAs   6eeEs   7iiIs   8uuUs 
2  9BaAs  10BbAs  11CcEs  12eeEs  13idIs  14 D dIs  15ufUs  16uuUs 
3 17BeEs  18ieEs  19ibIs  20BdIs  21ucUs  22ucUs  23 D uUs  24 D dUs 
4 25ieIs  26BeIs  27ucUs  28udUs  29 D uUs  30 D cUs  31 D dUs  32eeEs 
5 33ueUs  34ueUs  35 D uUs  36 D uUs  37 D cEs  38ecEs  39ieIs  40 D eIs 
6 41 D uEs  42 D cEs  43 D eIs  44iuIs  45 D cUs  46ucUs  47ueUs  48ueUs 
7 49 D uIs  50 D uIs  51 D eUs  52ueUs  53 D eUs  54ucUs  55ucUs  56ucUs 
8 57 D eUs  58 D eUs  59 D uUs  60ucUs  61 D eUs  62ucUs  63ucUs  64ucUs 

Return to top of page

© 2007 ChartsGraphsDiagrams.com