Genetics 3 - Human Origins and Evolution
Human origins: Homo
Homo habilis 2.3 Mya
communal living in caves
cared for young
Homo erectus 15,000-750,000 years ago
angled skull, possible speech
social, cooperative, tool-using
Neanderthals 28,000-150,000 years ago
larger brains, prominent brow arches
muscular jaws, distinct spacing of teeth
large, barrel-shaped chests
jewelry, intricate cave art
Homo sapiens from 40,000 years ago-
Study of evolution through comparison of DNA sequences, chromosome banding and genome structure.
Mutations occur in DNA over time.
Comparing two DNA sequences
• fewer changes => closer relation
more recent divergence
• more changes => more ancient divergence
Molecular Evolution: comparing genomes
Humans, chimps, and bonobos share 99.5% of their genes encoding proteins.
Traits defining “humanness” may be rare.
Molecular Evolution: comparing chromosomes
Human chromosomes banding is highly conserved between humans and the other great apes.
Molecular Evolution: comparing protein sequences
Comparison of DNA sequences indicates degree of evolutionary relation
Ancient DNA has been isolated from a few well preserved fossils
Human migration out of Africa
migrated out of
•Evolution of Homo sapiens occurred in multiple locations with interbreeding between populations.
•mtDNA sequences of indigenous peoples worldwide were compared to determine the common ancestral mtDNA sequence.
•Root of tree is in Africa
•Calibration of molecular clock with chimp outgroups indicate the common ancestral sequence existed 100,000 to 300,000 years ago.
DNA sequence comparisons of Asian and Native American populations
Anthropologists hypothesize three migrations to
cultural distinctions in Native American
Migration across the
Is a social movement advocating control of individual reproductive choices to change society
Sir Francis Galton, 1883, coined the term eugenics meaning “good in birth”
“The science of improvement of the human race germ-plasm through better breeding”
History of eugenics