1. Vertebrates Hair Mammary Glands Amniotic Egg Endothermy Four Limbs
Cartilagenous
Fish
Hagfish,
Lampreys
Bony
Fish
Amphibians
Mammals
Birds
Reptiles
Hair
Mammary Glands
Amniotic Egg
Endothermy
Four Limbs
Terrestrial Phase
Bony Skeleton
Swim Bladder
Skull
Backbone
Paired Fins
Jaws

2. Mammals Hair, mammary glands Most advanced nervous system
Learning important to
survival
Warm blooded
Humans are mammals

3. Humans are primate mammals
Class Mammalia
Order Primates
Prosimians (e.g. lemurs)
Tarsiers
Anthropoids (e.g. monkeys, hominoids)

4. Lemur
Tarsier
Macaque

5. Primates : Humble Beginning
Rabbit
Shrew
Shrew-like
Ancestor

6. Homininae : African Great Apes
Major Primate Groups
Family Hominidae
Old World
Monkeys
Orangutan
Chimp
Human
Tarsiiformes
Gibbons
Gorilla
Lemurs
New World
Monkeys
Homininae : African Great Apes
and Humans
Hominidea : Great Apes and Humans
Hominoidea : Apes and Humans

7. What Features Are Associated With Primate Evolution?
I. Sensory Adaptations
Protected, forward looking eyes with stereoscopic vision
Improved sight : more detail even in low light
Reduction of olfactory structures

8. What Features Are Associated With Primate Evolution?
II. Adaptations for tree-climbing and insectivory
Freely moving limbs and digits
Long mobile digits capable of grasping
Retention of tail as organ of balance
Evolution of upright body posture and extensive head rotation
Increased body size
Evolution of nervous system to give precise and rapid control of movement

9. Major Primate Groups Hasegawa et al. 1987 Orangutan Chimp Human
Family Hominidae
Old World
Monkeys
Orangutan
Chimp
Human
Tarsiiformes
Gibbons
Gorilla
Lemurs
New World
Monkeys
25 mya
12 mya
6 mya
Hasegawa et al. 1987
5 mya
38 mya
Estimated
Divergence Times

10. What Traits Do Humans and Apes Share?
Larger Brain
Absence of a tail
More erect posture
Greater flexibility of hips, ankles, wrist, thumb
DNA sequence similarity

11. Gorilla Chimpanzee Human
Horai et al (1995) Proc. Nat Acad Sci. 92:
Mito DNA (complete sequences)
Kim and Takenaka (1996) A. J. Phys. Anth. 100:
Y-chromosome DNA
Ruvolo (1997) Mol Biol Evol 10:
Examined 14 different DNA data sets
Satta et al (2000) Mol. Phyl. Evol 14:
Autosomal DNA (45 genes, 47,000 bp of DNA)
Paabo (2003) Nature 421:
Review of human and chimp/ape genomes.

12. Common Ancestor of Chimp/Human
Knuckle-walker?
Broad-fruit based diet
May have hunted
May have used tools
May have had complex social relationships:
(e.g.warfare, cannabalism, sharing,
teaching, compassion)

13. Our Understanding of Human Evolution is Primarily Based on Fossils

14. Can genes help explain our evolution?
- What type of changes (regulatory
or structural mutations?)
- How many genes are involved?

15. Candidate gene approach Microarray approach
Approaches to Identify Genetic/Genomic
Differences Between Chimps and Humans
Candidate gene approach
Microarray approach
Nucleotide substitution approach
Bioinformatic approach

16. Candidate gene approach: FOXP2
2 non-conservative amino acid substitutions in humans
- flanking genomic DNA showed signs of a selective sweep
Enard, W. et al Molecular evolution of FOXP2, a
gene involved in speech and language. Nature 418,

17. Signature of a Selective Sweep
Recombination
Mutation
Selection
Fixation
Favored
Allele
Reduced polymorphism
More rare alleles

18. FOXP2 plays a role in the development of
brain regions that are important for communication
FOXP2 is expressed highly in zebra finches during
the vocal learning period of development.
Haesler et al J. Neurosci 24:3164.
FOXP2 knock-out mice have altered motorsensory
functions and ultrasonic vocalizations.
Shu et al PNAS 102:9643.

19. Identified Human Accelerated Regions (HARs)
Pollard, KS et al. An RNA gene expressed during cortical
development evolved rapidly in humans. Nature Aug. 2006
Identified Human Accelerated Regions (HARs)
Scanned the 2/3 portion of the genome that is non-coding
Many of the identified regions are associated with
transcription factors and neurodevelopment genes.
The most dramatically changed element (HAR1) is a
novel RNA gene expressed during human cortical
development.

20. Details of the Screening Process
- Search chimpanzee genome sequence against rat and
mouse genome sequences. (96% identity > 100 bp)
- 35,000 regions identified
- Searched these regions in all other available amniote
genomes searching for regions with significant changes
in human.
- 49 regions identified with a statistically significant rate
increase in humans (96% in non-coding regions, 24%
next to a neurodevelopmental gene)