1. Lecture Outline 12/7/05 The human genome
Most of our DNA is non-coding
Various types of repetitive elements
Gene families
Some applications of genetic technologies
Future of genomics?
Course Review

2. On February 11, 2001, two groups published the sequence of the entire human genome

3. But that doesn’t mean we can read it . . .

4. Overview of the human genome
Exons (regions of genes coding
for protein, rRNA, tRNA) (1.5%)
Repetitive
DNA that
includes
transposable
elements
and related
sequences
(44%)
Introns and
regulatory
sequences
(24%)
Unique
noncoding
DNA (15%)
Repetitive
DNA
unrelated to
transposable
elements
(about 15%)
Alu elements
(10%)
Simple sequence
DNA (3%)
Large-segment
duplications (5–6%)

5. Numbers and types of genes in different eukaryotes
Most genes have uknown function

6. Areas of high and low gene density

7. Movement of eukaryotic transposable elements
Transposon
New copy of
transposon
is copied
DNA of genome
Insertion
Mobile transposon
(a) Transposon movement (“copy-and-paste” mechanism)
Retrotransposon
retrotransposon
RNA
Reverse
transcriptase
(b) Retrotransposon movement
Figure 19.16

8. Many genes occur in gene families
DNA
RNA transcripts
Non-transcribed
spacer
Transcription unit
18S
5.8S
28S
rRNA
(a) Part of the ribosomal RNA gene family
Heme
Hemoglobin
-Globin
-Globin
-Globin gene family
-Globin gene family
Chromosome 16
Chromosome 11 
  2  1   G A   
Embryo
Fetus
and adult
Adult
(b) The human -globin and -globin gene families
 Many genes occur in gene families
Ribosomal RNA genes
Globin genes
Figure 19.17

9. Histone gene distribution

10. Gene duplication due to unequal crossing over
Nonsister
chromatids
Transposable
element
Gene
Incorrect pairing
of two homologues
during meiosis
Crossover
and
Figure 19.18 

11. Evolution of the human -globin and -globin gene families
Ancestral globin gene      2 1   G A  
-Globin gene family
on chromosome 16
 -Globin gene family
on chromosome 11 
Evolutionary time
Duplication of
ancestral gene
Mutation in
both copies
Transposition to
different chromosomes
Further duplications
and mutations
Figure 19.19

12. Evolution of a new gene by exon shuffling
EGF
Epidermal growth
factor gene with multiple
EGF exons (green) F
Fibronectin gene with multiple
“finger” exons (orange)
Exon
shuffling
duplication K
Plasminogen gene with a
“kringle” exon (blue)
Portions of ancestral genes
TPA gene as it exists today
Figure 19.20 

13. Some other uses of genetic technology

14. Replacement of Neanderthals by Modern Humans
Generations before present
Currat and Excoffier 2004

15. Ovchinnikov et al 2000 Nature 404:490-493

16. Poaching Whales?

17. Data from Baker and Palumbi 1990
Minke whale
Sample #19a
Sample WS3
Sample #9
Sample #15
Sample #29
Sample #30
Sample #36
Sample #6
Sample #18
Sample #19b
Humpback whale
Gray whale
Blue whale
Sample #41
Sample #3
Sample #11
Sample WS4
Fin whale
Sei whale
Bryde’s whale
Bowhead whale
Right whale
Pygmy right whale
Sperm whale
Pygmy sperm whale
Sample #16
Harbor porpoise
Sample #13
Sample #28
Hector’s dolphin
Commerson’s dolphin
Killer whale
Data from Baker and Palumbi 1990

18. Particularly variable regions of DNA can be used as “genetic fingerprints”
Can any of these children be excluded from being the biological child of the father?
Mother
Father

19. The future? Patterns of expression? Regulatory networks?
Gene-> phenotype
Patterns of variation?
What is all the non-coding DNA?

20. Patterns of Gene Expression
“Gene Chips” or microarrays can compare expression levels of 1000s of genes at once

21. Understanding Variation