How old am I?

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1.7 million-year-oldhuman ancestor

DNA is passed from generation to generation, and therefore can tell us about relationships between species.

Fig 34.40

How are we related to our ancestors, and where did we come from?

Fig34.42

More than 10,000 years ago:Hunter-Gatherer

~10,000 to 200 years ago:Farming-Ranching

Last 200 years: Industrialization

Hunter-Gatherer

Agricultural

Industrial

The earth is covered in humans. How did this occur?

mitochondria

Traits coded for by mtDNA are inherited only through mother

Mom provides 50.000275% and Dad provides 49.999825% of DNA to offspring.

… because Mom provides 100% of mitochondrial DNA

Mitochondrial DNA comparisons can be used to trace ancestry:

Anna Anderson claimed she was Anastasia, but tests of her mtDNA and one of Anastasia’s maternal relatives did not match.

When did these migrations take place?

Non-Coding DNA is used for comparisons between individuals

Fig 1

Only DNA that is successfully passed on can be used to trace the past.

Fig 1 and 4

As DNA is passed on mutations take place

Fig 4

Fig 4

By determining the average time between mutations, we can estimate the time of the last common ancestor.

Fig 4

The mutation rate in human mtDNA is one nucleotide change per 20,000 years.ORA difference of one nucleotide between two people indicates a common relative 10,000 years ago.

Multiregional hypothesis

“Out of Africa” hypothesis

Two hypotheses about the origin of H. sapiens

7 Daughters of Eve, fig. 1

Relationships of different populations using mtDNA

~150,000ya

Multiregional hypothesis

“Out of Africa” hypothesis

Two hypotheses about the origin of H. sapiens

X

Fig 3

Newer Data: Estimated time of divergence for several DNA regions

Fig 3

Newer Data: Estimated time of divergence for several DNA regions

Multiregional hypothesis

“Out of Africa” hypothesis

Two hypotheses about the origin of H. sapiens

X

Multiregional hypothesis: disproved by mtDNA data

“Out of Africa” hypothesis: disproved by other DNA data

Two hypotheses about the origin of H. sapiens

?

7 Daughters of Eve, fig. 2

Relationships of different people using mtDNA.

7 Daughters of Eve, fig. 2

Relationships of different people using mtDNA.

7 Daughters of Eve, fig. 2

Relationships of different people using mtDNA.

“Man’s Most Dangerous Myth: the Fallacy of Race” by Ashley Montagu

“Man’s Most Dangerous Myth: the Fallacy of Race” by Ashley Montagufirst published in 1942

7 Daughters of Eve, fig. 2

From Science v298 12/20/02 pg 2381

•93-95% of genetic variation within population.

•3-5% of genetic variation occurs between populations.

Relationships of different people using mtDNA.

There is no genetic definition of race.

Humans have been constantly moving and migrating. Any geographic location contains people with DNA from many different other areas...

Proposed model of human evolution/migration

Out of Africa of Homo erectus

Out of Africa

Out of Africa of Homo sapiens

Expansion from Asia to Africa

Additional migrations

Fig 9

Humans have been constantly moving and migrating. Any geographic location contains people with DNA from many different other areas...

Next: Are wegeneticallyProgramedto be racist?

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