23. Downloaded from www.sciencemag.org on March 12, 2013 Solenopsis invicta fire ants are
REPORTS
a big problem!
very well studied!
Ascunce et al 2011
24. Solenopsis invicta fire ant:
two social forms
Single-queen form: Multiple-queen form:
•1 large queen
•Independent founding
•Highly territorial
•Many sizes of workers
•2-100 smaller queens
•Dependent founding
•No inter-colony aggression
•All workers similar size
25. L. Keller
Population genetics: Allozyme screen
Fire ants
+
Ken Ross
+ “starch gel”
1 2 3
26. Allozyme screen Social form associated to Gp-9 locus
Frequency of
the most
common allele
Ddh-1!
Pro-5!
Locus!
1.0!
0.9!
0.8!
0.7!
0.6!
0.5!
0.4!
0.3!
Single queen!
Multiple queen!
Est-4!
G3pdh-1! Ca-4!
Est-6!
Pgm-4!
Acy-1!
Pgm-1!
acoh-1!
Pgm-3!
Acoh-5!
Aat-2!
Gp-9!
Ken Ross and colleagues
Laurent Keller and colleagues
27. Social form completely associated to Gp-9 locus
Single queen form Multiple queen form
Ken Ross and colleagues
Laurent Keller and colleagues
28. Social form completely associated to Gp-9 locus
Single queen form Multiple queen form
BB BB Bb bb
Ken Ross and colleagues
Laurent Keller and colleagues
29. Social form completely associated to Gp-9 locus
Single queen form Multiple queen form
x
BB BB Bb bb
Gp-9 bb females rare
Ken Ross and colleagues
Laurent Keller and colleagues
30. Social form completely associated to Gp-9 locus
Single queen form Multiple queen form
BB BB Bb
Ken Ross and colleagues
Laurent Keller and colleagues
31. Social form completely associated to Gp-9 locus
Single queen form Multiple queen form
BB BB Bb
x
Ken Ross and colleagues
Laurent Keller and colleagues
32. Social form completely associated to Gp-9 locus
Single queen form Multiple queen form
BB BB Bb
x x
Ken Ross and colleagues
Laurent Keller and colleagues
33. Social form completely associated to Gp-9 locus
Single queen form Multiple queen form
(< 5% ) (>15% )
BB BB Bb
x x x
Ken Ross and colleagues
Laurent Keller and colleagues
34. Social form completely associated to Gp-9 locus
• Is this gene the single überregulator?
35. Social form completely associated to Gp-9 locus
• Is this gene the single überregulator?
•Only 14 allozyme markers were used
maybe 1/14th of the genome?
Ddh-1!
Pro-5!
Locus!
1.0!
0.9!
0.8!
0.7!
0.6!
0.5!
0.4!
0.3!
Single queen!
Multiple queen!
Est-4!
G3pdh-1! Ca-4!
Est-6!
Pgm-4!
Acy-1!
Pgm-1!
acoh-1!
Pgm-3!
Acoh-5!
Aat-2!
Gp-9!
36. This changes
454 everything.
Illumina
Solid...
Any lab can
sequence
anything!
37.
38. Are other genes linked to Gp-9?
Sequenced:
•Genome
of a Gp-9 B ♂
Sequencing from haploid males (for easier assembly):
45× (330bp-insert paired reads) + (normal single-Single ♂:
His brothers:
B 20x
11×
4×
(8,000 & 20,000bp-insert paired reads)
41. Deuterostomia 173
Nematoda 25
Cnidaria 100
Not assigned 274
★ Expansion of lipid-processing gene families (for Cuticular Hydrocarbons)
420 putative olfactory receptors 3
SiOR03038
SiOR04609+SiOR06843+1 1
SiOR06723+12
★ (more than any other insect!)
SiOR04648+★ Functional DNA-methylation system
SiOR00899+6 SiOR02694+4
★Ant-specific duplication and subfunctionalization
of vitellogenin (in bees: involved in reproduction & division of labor)
SiOR00899+8 SiOR04648+7
SiOR04648+6
SiOR04171+17
SiOR04171+29
SiOR04171+14
SiOR04609+5
SiOR01321
SiOR04609+19
SiOR00899+12 SiOR05901+1
SiOR04171+3
12 SiOR01224+SiOR04510+SiOR04510+16 13
SiOR04171+25 SiOR06577
SiOR04171+24
SiOR01629+3 SiOR01968+26
SiOR04171+21 SiOR06792+6
SiOR02883+2
SiOR05431+SiOR01858+1 1
SiOR05431+4
SiOR04510+7 SiOR01968+21
SiOR05431+3 SiOR04510+6
SiOR01629+1
SiOR01968+7 SiOR01629+6
SiOR05285+2
SiOR03663
SiOR00899+13
Wurm et al 2011
significance of these duplication events in vitellogenins, odor
perception genes, and a family of lipid-processing genes. We also
discuss additional features of interest in the fire ant genome rel-evant
to the complex social biology of this species, including sex
determination genes, DNA methylation genes, telomerase, and
the insulin and juvenile hormone pathways.
Vitellogenins. In contrast to other insects that mainly have only one
or two vitellogenins, the fire ant genome harbors four adjacent
after duplication to acquire caste-specific functions.
Odor Perception. Consistent with studies in other insects, we find
a single S. invicta ortholog to DmOr83b, a broadly expressed ol-factory
receptor (OR) required to interact with other ORs for
Drosophila and Tribolium castaneum olfaction (30–32). Beyond
OR83b, OR number varies greatly between insect species. Blast
searches and GeneWise searches using an HMM profile con-structed
with aligned ORs from N. vitripennis (33) and Pogono-myrmex
barbatus identified more than 400 loci in the S. invicta
genome with significant sequence similarity to ORs. Preliminary
work on gene model reconstruction identified 297 intact full-length
proteins. Many S. invicta ORs are in tandem arrays (Fig.
S2A) and derive from recent expansions. S. invicta may thus har-bor
the largest identified insect OR repertoire because there are
10 ORs in Pediculus humanus (34), 60 in Drosophila, 165 in
A. mellifera, 225 in N. vitripennis (33), and 259 in T. castaneum
(32). The large numbers of N. vitripennis and T. castaneum ORs
are thought to be due to current or past difficulties in host and
food finding. As has been suggested for A. mellifera (35), the large
number of S. invicta ORs may result from the importance of
chemical communication in ants. The odorant-binding proteins
(OBPs) are another family of genes also known to play roles in
chemosensation in Drosophila (36). Intriguingly, the social orga-nization
of S. invicta colonies is completely associated with se-
No hits 3424
Fig. 2. Taxonomic distribution of best blastp hits of S. invicta proteins to the
nonredundant (nr) protein database (E < 10−5). Results were first plotted
using MEGAN software (22) and then branches with fewer than 20 hits were
removed, branch lengths were reduced for compactness, and tree topology
was adjusted to reflect consensus phylogenies (23, 24).
2,330,000 bp 2,360,000 bp A
Vg4 Vg1 Vg3 Vg2
B Solenopsis Vg1 C
Solenopsis Vg4
Solenopsis Vg2
Solenopsis Vg3
Apis Vg
Bombus Vg
Nasonia Vg1
Pteromalus Vg
Nasonia Vg2
Encarsia Vg
Pimpla Vg
Athalia Vg
Apocrita
Tenthedinoidea
Vespoidea
Apoidea
Aculeata
Chalcidoidea
25000 Vg2 Vg3
20000
15000
10000
5000
Vg1 Vg4
* ***
600
500
400
300
200
100
Ichneumonoidea 0
*** ***
Q W Q W Q W Q W
142 389 1 40 17820 1.4 9269 0.6
0
Fig. 3. S. invicta vitellogenins. (A) Four vitellogenins are located within a single 40,000-bp region of the S. invicta genome. (B) Parsimony tree of known hy-menopteran
EVOLUTION
0.05
SiOR04648+10
SiOR01968+4
SiOR00899+7
SiOR02814+3
SiOR04171+6
SiOR04609+4
SiOR00330+28
SiOR02694+25
SiOR04609+20
SiOR05285+6
25
SiOR04510+15
SiOR00330+18 SiOR04609+23
SiOR01968+23
SiOR03952+4
SiOR04648+16
SiOR05901+2
SiOR02944+4
SiOR01968+5
SiOR04171+19
SiOR04648+5
SiOR10535+3
SiOR06723+2
SiOR01968+9
SiOR02883+1
SiOR00899+3
SiOR04171+1
SiOR01629+11
SiOR04171+10
SiOR04171+13
SiOR02694+3
SiOR04171+20
SiOR02694+35
SiOR04171+15
SiOR04609+7
SiOR05118+2
SiOR07837+2
SiOR02694+27
SiOR01968+10
SiOR04648+17
SiOR01968+19
SiOR02694+17
13
SiOR01968+6
SiOR00330+20
SiOR02648+2
SiOR02659+2
SiOR01968+16
SiOR00899+11
SiOR02974
SiOR04171+2
SiOR03952+2
SiOR06792+2
SiOR04510+4
SiOR04171+28
SiOR05285+5
9 SiOR00899+15 SiOR04648+3
SiOR02694+36
SiOR10535+1
SiOR02694+19
SiOR02694+23
SiOR02694+1
SiOR04609+14
SiOR01122
9
SiOR02694+34
SiOR01629+8
SiOR04648+8
SiOR04510+8
SiOR06573
SiOR02944+1
26
SiOR00330+1
SiOR02694+15
SiOR05285+7
SiOR00899+5
SiOR04609+10
SiOR04609+3 SiOR04339
SiOR08068
SiOR04510+2
SiOR05285+8
SiOR01573+4
SiOR04171+8
SiOR01858+2 SiOR01968+2
SiOR01968+1
SiOR02694+5
SiOR01968+3
SiOR06723+3
SiOR01968+15
SiOR05285+1
SiOR00899+4
SiOR04609+22
SiOR04171+9
SiOR02694+9 SiOR02648+1
SiOR06792+3
SiOR01573+2
SiOR02694+20
SiOR10542
SiOR04609+15
SiOR02694+8
SiOR00330+16
SiOR00899+2
SiOR02694+10
SiOR04510+9
SiOR05285+3
SiOR04609+2
SiOR05285+11 SiOR02694+14
SiOR01573+1
SiOR00613
SiOR01968+22
SiOR00899+9
SiOR06843+2
SiOR02694+37
SiOR00899+1
SiOR04609+9
SiOR05431+2 SiOR10535+2
SiOR00330+15
SiOR02694+18
SiOR01224+2
SiOR04510+11
23
SiOR02694+29
SiOR05416
SiOR05285+10 SiOR02694+2
SiOR01629+9
SiOR08341 SiOR02694+22
SiOR01224+1
SiOR01968+12
SiOR02694+7
SiOR02944+2
SiOR03952+3
SiOR01968+8
SiOR04609+24
SiOR02694+30
SiOR01629+10
SiOR04510+14
SiOR00565 SiOR05118+3
SiOR00330+14
SiOR02694+38 SiOR04609+8
SiOR04171+16
SiOR10455
SiOR04609+16
SiOR04609+21
SiOR02694+28 SiOR02659+1
SiOR04171+5 SiOR00330+29
SiOR01968+14
SiOR03983
SiOR00330+27
SiOR05285+4
SiOR04510+1
SiOR04609+17 SiOR00330+5
SiOR02694+21
SiOR02814+4
SiOR00330+7
SiOR02694+31
SiOR04648+2
SiOR02694+39
SiOR01968+25
SiOR04609+11
SiOR02694+11
SiOR06792+1
SiOR04171+4
SiOR01629+5
SiOR00330+21
SiOR04648+15
SiOR00330+6SiOR02694+16
11
SiOR04648+4
SiOR00330+3
SiOR06535
SiOR04171+7
SiOR10493
SiOR02694+32
SiOR06792+4
SiOR04510+3
SiOR06890
SiOR01968+20
SiOR04609+12
SiOR04171+3
SiOR01968+18
SiOR01968+11
SiOR04609+13
SiOR01629+12
SiOR00330+22
SiOR02694+33
SiOR00330+13
SiOR01573+3
SiOR05118+1
SiOR02944+3
SiOR04171+26
SiOR00899+14
SiOR02694+13
SiOR00330+24
SiOR00330+19
SiOR04171+27
SiOR02694+24
SiOR04510+5
SiOR07090
SiOR03952+1
SiOR04510+10
SiOR00330+17
SiOR02694+26
SiOR02814+2
SiOR00330+11
SiOR04171+18
SiOR01968+17
SiOR00330+10
SiOR00330+9
SiOR01629+2
SiOR04171+11
SiOR04510+12
SiOR00330+8
SiOR02694+6
SiOR01968+13
SiOR00330+4 SiOR04609+18
SiOR00899+10
SiOR00330+12
SiOR00330+31
SiOR06843+1
SiOR07837+1
SiOR00330+2
SiOR01629+4
SiOR04648+1
SiOR01968+24
SiOR04171+23
SiOR01629+7 SiOR04648+14
SiOR06792+5
SiOR02883+3
SiOR02694+12
SiOR05118+4
SiOR04171+22
SiOR01080 SiOR04609+6
SiOR02814+1
SiOR00330+30
SiOR05285+12
Genome of a Gp-9 B ♂ fire ant
Wurm et al 2011
42. Are other genes linked to Gp-9?
Social form completely associated to Gp-9 locus
Single queen form Multiple queen form
(< 5% ) (>15% )
BB BB Bb
x x x
43. Are other genes linked to Gp-9?
Sequenced:
•Genome of a Gp-9 B ♂
•Genome of a Gp-9 b ♂
RAD sequencing
“Next Generation Genotyping.”
44. RAD sequencing
“Next Generation Genotyping.”
Bb
unfertilised eggs
haploid ♂
Gp-9 B Gp-9 b Gp-9 B Gp-9 b Gp-9 b Gp-9 B
38 B♂ & 38 b♂
45. RAD sequencing of haploid ♂ for SNP
EcoR1 EcoR1 EcoR1
Gp-9 B
discovery & genotyping
46. RAD sequencing of haploid ♂ for SNP
EcoR1 EcoR1 EcoR1
AACTG
AACTG
AACTG
AACTG
Gp-9 B
discovery & genotyping
Gp-9 B
47. RAD sequencing of haploid ♂ for SNP
Gp-9 B
AACTG
Gp-9 B
Gp-9 B
GGCCT
Gp-9 B
Gp-9 B
AAGGT
Gp-9 B
Gp-9 b
CCAGT
Gp-9 b
Gp-9 b
TAAAT
Gp-9 b
Gp-9 b
GGAAT
Gp-9 b
38 Gp-9 B
males
38 Gp-9 b
males
discovery & genotyping
48. RADseq: sequencing the same 0.01% of the
genome in many individuals
Identify polymorphism
individual x locus
genotype table
A B C D E F
L1 A C A A C C
L2 G G T - T G
L3 - A G A - G
L4 C - - G G C
L5 T T C T C -
L6 G A A - - G
2419 loci
38 B 38 b
PCA: Principal Component Analysis
Amount of variance explained per principal component
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20+
% Variance Explained
0 5 10 15 20 25 30
12.7%
6.1% 5.4% 4.8% 4.7% 3.9% 3.5% 3.2% 3.1% 2.9% 2.8% 2.6% 2.4% 2.3% 2.2% 2.0% 1.9% 1.7% 1.6%
30.2%
49. Principal Components: PC2 vs PC3
pc: 2 % variance: 6.073
pc: 3 % variance: 5.441
0.2
0.1
0.0
-0.1
-0.2
-0.2 -0.1 0.0 0.1 0.2
Gp-9 B
Gp-9 b
50. Principal Components: PC1 vs PC2
pc: 1 % variance: 12.666
pc: 2 % variance: 6.073
0.2
0.1
0.0
-0.1
-0.2
-0.10 -0.05 0.00 0.05 0.10 0.15
Gp-9 B ♂
Gp-9 b ♂
52. Sex chromosomes
X Y
“Social chromosomes”
Gp-9 B
Gp-9 b
?
SB Sb
Why non-recombining?
53. Structural differences between B and b
likely inhibit recombination
Small portion (200,000bp) of social chromosome
SB
Sb
54. Structural differences between B and b
likely inhibit recombination
Gp-9B
genetic map
SB Sb
a Gp-9 B male A22
A22
Gp-9 b male
male Gp-9 b male
E17
E3
Gp-9 B male SB Sb
Gp-9B
genetic map
A22
A22
E17
E17
E3
SB Sb
Gp-9B
genetic map
E3
b SB Sb
Gp-9B
genetic map
E17
E3
Gp-9 b male
Flourescence in situ
Hybridization
John Wang @ Taipei
56. X
♀
♂
X X Y
Single queen colony Multiple queen colony
Likely several
rearrangements
•Prediction:
SB SB SB Sb
Differences between SB and Sb?
•genes?
Region contains 800 genes! only small differences
⟹ Prediction: directional (antagonistic?) selection?
Sb is degenerating?
57. • More, larger repetitive DNA in Sb compared to SB
• larger introns in Sb
• larger intergenic regions in Sb
• assembly worse (smaller scaffolds) in Sb
• increased dN/dS
SB
Sb
[a] vs. [c]: p 10-7
[b] vs. [c]: p 10-4
Gp-9B male Gp-9b male
6,000,000
5,000,000
4,000,000
3,000,000
2,000,000
1,000,000
Region:
Genome assembly:
Normally recombining
regions from all 16
linkage groups
Normally recombining
regions from all 16
linkage groups
Sb region without
recombination
in Gp-9 Bb queens
SB region without
recombination
in Gp-9 Bb queens
Scaffold length (bp)
0
[a] [a], [b] [a] [c]
SB Sb
Sb is degenerating?
58. X
♀
♂
X X Y
Single queen colony Multiple queen colony
Likely several
rearrangements
•Prediction:
SB SB SB Sb
Differences between SB and Sb?
•genes?
Region contains 800 genes! only small differences
⟹ Prediction: directional (antagonistic?) selection?
Sb is degenerating?
•Probably ♂ haploidy: strong purifying selection
⟹ slower degeneration
59. Formica selysi
Alpine silver ant
Common ancestor with fire ant: 130 MYA
Purcell et al 2014 Convergent social chromosome architecture
J Meunier
Single queen form Multiple queen form
60. ≠ social chromosomes
Purcell et al 2014
Solenopsis
invicta social
chromosome
Formica selysi
social
chromosome
62. Summary
Ants are cool.
Fire ant Solenopsis invicta queen number determined by Gp-9 genotypes:
•only BB workers ➔ single BB queen
•with Bb workers ➔ multiple Bb queens
Genome sequencing + RAD Genotyping 500 individuals
•Gp-9 marks ~4% of genome ➔ social chromosomes:
SB is like X; Sb is like Y
Structural differences between SB and Sb ➔ no recombination
Formica selysi: Convergent evolution of social chromosomes
63. Generally
genome evolution social evolution
Single- vs. Multiple queenness
in fire ants
in similar independent species
•one or many loci?
•one or many genes?
•convergence?
Social parasitism
Strengths of selection in
social evolution
concepts mechanisms
Candidate gene studies
Vitellogenin
Sex determination genes
Molecular response to
social upheaval
Caste differentiation (Medically
relevant)
Tools for genomics work on emerging model organisms
82. GeneValidator
Run on:
whole geneset: identify most problematic predictions
alternative models for a gene (choose best)
individual genes (while manually curating)
84. Gene prediction
Dozens of software algorithms: dozens of predictions
TTCAATAATAATATCAAATTCACATTCAAAGCTTTCAAGTTAGACAAAAGTTTTAATGCCGTTTTtACCTGTTTTtGAAAAGGTAATTTTCTTTAGATATATACAGTTTGTAATaTTAGGTATTTTATAAACAGTGTGTATATTTCTTACAATATAAAAGACACAATTGCAAACTAGCATGATTGTAAACAATTGCTAAACGGATCAATATAAATTAAAATTGTAATATTAAGTATCAAACCGATAATTTTTATEvidence
20% failure rate:
•missing pieces
•extra pieces
•incorrect merging
•incorrect splitting
Visual inspection... and
manual fixing required.
1 gene = 20 minutes to 3 days
15,000 genes * 20 species =
impossible.
Yandell Ence 2013 NRG
Consensus:
85.
86. Afra: Crowdsourcing gene model curation
Challenges
• Recruiting retaining contributors
Begin
• Ensuring quality
Create initial tasks
Needs curation
Curate
Being curated
Curate
Being curated
Curate
Being curated
Submit Submit Submit
Auto-check
Done
Inconsistent: create
“review” task
Consistent:
create next required task
87.
88.
89.
90. Timelines
• Rolled out to:
• 8 MSc students
• 20 3rd year students
• Need to improve tutorials/guidance/documentation
• Roll out to 200 first years (few months)
• Expand
91. Summary
Ants are cool.
Fire ant Solenopsis invicta queen number determined by Gp-9 genotypes:
•only BB workers ➔ single BB queen
•with Bb workers ➔ multiple Bb queens
Genome sequencing + RAD Genotyping 500 individuals
•Gp-9 marks ~4% of genome ➔ social chromosomes:
SB is like X; Sb is like Y
Structural differences between SB and Sb ➔ no recombination
Formica selysi: Convergent evolution of social chromosomes
A few tools for genomics:
• http://sequenceserver.com (easy custom BLAST server)
• http://bionode.io (Agile data analysis workflows)
• http://afra.sbcs.qmul.ac.uk (Crowdsourcing gene feature curation)
• http://genevalidator.sbcs.qmul.ac.uk Identifying gene prediction
problems
92. QMUL lab (R Pracana, B Vieira, E
Stolle, A Priyam, I Moghul et al)
Laurent Keller lab (J WANG, D
SHOEMAKER,O RIBA-GROGNUZ,
M Nipitwattanaphon)
Michel Chapuisat, Jess Purcell,
Alan Breslford, Nicolas Perrin
Ecology Evolution Vital-IT
@ Lausanne
Organismal Biology Psych
@ Queen Mary
http://wurmlab.github.io
M Corona, S Nygaard, BG Hunt, KK Ingram, L
Falquet, M Nipitwattanaphon, D Gotzek, MB Dijkstra,
J Oettler, F Comtesse, CJ Shih, WJ Wu, CC Yang, J
Thomas, E Beaudoing, S Pradervand, V Flegel, ED
Cook, R Fabbretti, H Stockinger, L Long, WG
Farmerie, J Oakey, JJ Boomsma, P Pamilo, SV Yi, J
Heinze, MAD Goodisman, L Farinelli, K Harshman, N
Hulo, L Cerutti, Ioannis Xenarios