Contractions and expansions in gene size and number - Human Gene Evolution - page 365

Loss of AGGCGGAGG motif

Human (Homo sapiens)
(CGG) 9 AGG(CGG) 9 AGG(CGG) 9

Acquisition of
3' AGG

(CGG) 9 AGGCGGAGG(CGG) 7 AGG(CGG) 9
AGG(CGG) 3 cassette

Loss of distal AGG

(CGG) 9 AGGCGGAGG(CGG) 17
(5-7 Mya)

Gorilla (Gorilla gorilla)
(CGG) 8 AGGCGGAGG(CGG) 3 AGG(CGG) 3 AGG(CGG) 3 AGG(CGG) 3
Chimpanzee (Pan troglodytes)
(CGG) 9 AGGCGGAGG(CGG) 16 AGGCGG
Pygmy chimpanzee (Pan paniscus)
(CGG) 2 CAG(CGG) 12 AGG(CGG) 7 AGG(CGG) 15
Orangutan (Pongo pygmaeus)
(CGG) 8 AGGCGGAGG(CGG) 2 AGG(CGG) 3 AGG(CGG) 8
Gibbon (Hylobateslar)
CGGCGACGGCGA(CGG) 2 CGACGGCGA(CGG) 3 AGG(CGG) 11

Proliferation of
AGG interspersions

Branch position is variable

(CGG) 9 AGGCGGAGG(CGG) 2 AGG(CGG) 14
Pongid/Hominid (19 Mya)

Loss of AGGCGGAGG motif; recent acquisition of CAG

29

(CGG) 14 AGG(CGG) 6
Hominid ancestor
25 Mya

21
repeats

Acquisition of 3' AGG

Acquisition of
5' CGA interruptions

22

Acquisition of
1st AGG

CGGCGACGCCGA(CGG) 2 CGACGGCGA(CGG) 6 AGG(CGG) 6
Hylobatid

Siamang (Hylobates syndactylus)
CGGCGACGGCGA(CGG) 2 CGA(CGG) 5 AGG(CGG) 3 AGG(CGG) 7
Allen's monkey (Allenopithecus nigroviridis)
(CGG) 20
Baboon (Papio)
(CGG) 12 CGGG(CGG) 19
Drill (Mandrillus leucophaeus)
(CGG) 9 CGGG(CGG) 14
Rhesus monkey (Macaca rhesus)
(CGG) 13 CGGGCGGCGGG(CGG) 14
Duc's langur (Pygathrix nemaeus)
(CGG) 10
Proboscis monkey (Nasalis larvatus)
(CGG) 7

Loss of CGGG interruption
(Cercopithecinae)
(Papionae)

Acquisition of
CGGG interruption

(CGG) 13 CGGG
Cercopithecid

Catarrhine ancestor
(31 Mya)
(CGG) 7

14

*

(CGG) 7
Cercopithecoid
ancestor

7
repeats

Acquisition of CGGG interruption

7

Maintenance of
ancestral state

(CGG) 7
Colobid

Golden monkey (Rhinopithecus roxellana)
(CGG) 7
Colobus monkey (Colobus guereza)
(CGG) 8

Lemur (Lemur fulvianus)
(CGG) 14

Figure 8.13. Hypothetical schema for the evolution of the FMR1 CGG repeat in Old World monkeys (after Eichler et al ., 1995). Mya, million years
ago.