Incidental Mutation 'R6263:Pax6'
| ID |
506801 |
| Institutional Source |
Beutler Lab
|
| Gene Symbol |
Pax6
|
| Ensembl Gene |
ENSMUSG00000027168 |
| Gene Name |
paired box 6 |
| Synonyms |
Pax-6, Dickie's small eye, Gsfaey11, 1500038E17Rik, Dey, AEY11 |
| MMRRC Submission |
044437-MU
|
| Accession Numbers |
|
| Essential gene? |
Essential
(E-score: 1.000)
|
| Stock # |
R6263 (G1)
|
| Quality Score |
225.009 |
|
Status
|
Validated
|
| Chromosome |
2 |
| Chromosomal Location |
105499245-105527709 bp(+) (GRCm39) |
| Type of Mutation |
critical splice donor site (2 bp from exon) |
| DNA Base Change (assembly) |
T to C
at 105523199 bp (GRCm39)
|
| Zygosity |
Heterozygous |
| Amino Acid Change |
|
| Ref Sequence |
ENSEMBL: ENSMUSP00000129344
(fasta)
|
| Gene Model |
predicted gene model for transcript(s):
[ENSMUST00000090391]
[ENSMUST00000090397]
[ENSMUST00000111082]
[ENSMUST00000111083]
[ENSMUST00000111085]
[ENSMUST00000111086]
[ENSMUST00000111087]
[ENSMUST00000111088]
[ENSMUST00000167211]
|
| AlphaFold |
P63015 |
| Predicted Effect |
probably null
Transcript: ENSMUST00000090391
|
| SMART Domains |
Protein: ENSMUSP00000087870
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
4 |
142 |
7.36e-86 |
SMART |
|
low complexity region
|
188 |
199 |
N/A |
INTRINSIC |
|
HOX
|
224 |
286 |
4.93e-26 |
SMART |
|
low complexity region
|
295 |
308 |
N/A |
INTRINSIC |
|
low complexity region
|
401 |
409 |
N/A |
INTRINSIC |
|
low complexity region
|
412 |
426 |
N/A |
INTRINSIC |
|
| Predicted Effect |
probably null
Transcript: ENSMUST00000090397
|
| SMART Domains |
Protein: ENSMUSP00000087878
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
4 |
128 |
6.11e-92 |
SMART |
|
low complexity region
|
174 |
185 |
N/A |
INTRINSIC |
|
HOX
|
210 |
272 |
4.93e-26 |
SMART |
|
low complexity region
|
281 |
294 |
N/A |
INTRINSIC |
|
low complexity region
|
387 |
395 |
N/A |
INTRINSIC |
|
low complexity region
|
398 |
412 |
N/A |
INTRINSIC |
|
| Predicted Effect |
probably null
Transcript: ENSMUST00000111082
|
| SMART Domains |
Protein: ENSMUSP00000106711
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
4 |
128 |
6.11e-92 |
SMART |
|
low complexity region
|
174 |
185 |
N/A |
INTRINSIC |
|
HOX
|
210 |
272 |
4.93e-26 |
SMART |
|
low complexity region
|
281 |
294 |
N/A |
INTRINSIC |
|
low complexity region
|
387 |
395 |
N/A |
INTRINSIC |
|
low complexity region
|
398 |
412 |
N/A |
INTRINSIC |
|
| Predicted Effect |
probably null
Transcript: ENSMUST00000111083
|
| SMART Domains |
Protein: ENSMUSP00000106712
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
4 |
128 |
6.11e-92 |
SMART |
|
low complexity region
|
174 |
185 |
N/A |
INTRINSIC |
|
HOX
|
210 |
272 |
4.93e-26 |
SMART |
|
low complexity region
|
281 |
294 |
N/A |
INTRINSIC |
|
low complexity region
|
387 |
395 |
N/A |
INTRINSIC |
|
low complexity region
|
398 |
412 |
N/A |
INTRINSIC |
|
| Predicted Effect |
probably null
Transcript: ENSMUST00000111085
|
| SMART Domains |
Protein: ENSMUSP00000106714
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
4 |
142 |
7.36e-86 |
SMART |
|
low complexity region
|
188 |
199 |
N/A |
INTRINSIC |
|
HOX
|
224 |
286 |
4.93e-26 |
SMART |
|
low complexity region
|
295 |
308 |
N/A |
INTRINSIC |
|
low complexity region
|
401 |
409 |
N/A |
INTRINSIC |
|
low complexity region
|
412 |
426 |
N/A |
INTRINSIC |
|
| Predicted Effect |
probably null
Transcript: ENSMUST00000111086
|
| SMART Domains |
Protein: ENSMUSP00000106715
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
4 |
142 |
7.36e-86 |
SMART |
|
low complexity region
|
188 |
199 |
N/A |
INTRINSIC |
|
HOX
|
224 |
286 |
4.93e-26 |
SMART |
|
low complexity region
|
295 |
308 |
N/A |
INTRINSIC |
|
low complexity region
|
401 |
409 |
N/A |
INTRINSIC |
|
low complexity region
|
412 |
426 |
N/A |
INTRINSIC |
|
| Predicted Effect |
probably null
Transcript: ENSMUST00000111087
|
| SMART Domains |
Protein: ENSMUSP00000106716
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
4 |
128 |
6.11e-92 |
SMART |
|
low complexity region
|
174 |
185 |
N/A |
INTRINSIC |
|
HOX
|
210 |
272 |
4.93e-26 |
SMART |
|
low complexity region
|
281 |
294 |
N/A |
INTRINSIC |
|
low complexity region
|
387 |
395 |
N/A |
INTRINSIC |
|
low complexity region
|
398 |
412 |
N/A |
INTRINSIC |
|
| Predicted Effect |
probably null
Transcript: ENSMUST00000111088
|
| SMART Domains |
Protein: ENSMUSP00000106717
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
low complexity region
|
2 |
17 |
N/A |
INTRINSIC |
|
HOX
|
39 |
101 |
4.93e-26 |
SMART |
|
low complexity region
|
110 |
123 |
N/A |
INTRINSIC |
|
| Predicted Effect |
probably null
Transcript: ENSMUST00000167211
|
| SMART Domains |
Protein: ENSMUSP00000129344
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
4 |
142 |
7.36e-86 |
SMART |
|
low complexity region
|
188 |
199 |
N/A |
INTRINSIC |
|
HOX
|
224 |
286 |
4.93e-26 |
SMART |
|
low complexity region
|
295 |
308 |
N/A |
INTRINSIC |
|
low complexity region
|
401 |
409 |
N/A |
INTRINSIC |
|
low complexity region
|
412 |
426 |
N/A |
INTRINSIC |
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000135412
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000145744
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000155081
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000123063
|
| SMART Domains |
Protein: ENSMUSP00000121345
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
HOX
|
9 |
71 |
2.5e-28 |
SMART |
|
low complexity region
|
80 |
93 |
N/A |
INTRINSIC |
|
Blast:PAX
|
121 |
169 |
6e-24 |
BLAST |
|
low complexity region
|
186 |
194 |
N/A |
INTRINSIC |
|
low complexity region
|
197 |
211 |
N/A |
INTRINSIC |
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000147946
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000140173
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000138365
|
| SMART Domains |
Protein: ENSMUSP00000117154
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
low complexity region
|
4 |
15 |
N/A |
INTRINSIC |
|
PAX
|
33 |
192 |
4.87e-77 |
SMART |
|
low complexity region
|
238 |
249 |
N/A |
INTRINSIC |
|
SCOP:d1b72a_
|
254 |
291 |
2e-4 |
SMART |
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000153011
|
| SMART Domains |
Protein: ENSMUSP00000118457
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
PAX
|
2 |
109 |
4.98e-42 |
SMART |
|
low complexity region
|
155 |
166 |
N/A |
INTRINSIC |
|
Pfam:Homeobox
|
192 |
218 |
7.7e-9 |
PFAM |
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000146803
|
| SMART Domains |
Protein: ENSMUSP00000133346
Gene: ENSMUSG00000027168
| Domain | Start | End | E-Value | Type |
|---|
|
Blast:PAX
|
1 |
62 |
1e-26 |
BLAST |
|
HOX
|
74 |
136 |
4.93e-26 |
SMART |
|
low complexity region
|
145 |
158 |
N/A |
INTRINSIC |
|
Blast:PAX
|
186 |
234 |
3e-23 |
BLAST |
|
low complexity region
|
251 |
259 |
N/A |
INTRINSIC |
|
low complexity region
|
262 |
276 |
N/A |
INTRINSIC |
|
| Predicted Effect |
noncoding transcript
Transcript: ENSMUST00000154643
|
| Coding Region Coverage |
- 1x: 99.9%
- 3x: 99.7%
- 10x: 98.4%
- 20x: 95.7%
|
| Validation Efficiency |
97% (66/68) |
| MGI Phenotype |
FUNCTION: This gene encodes a homeobox-containing protein that functions as a regulator of transcription. It plays a key role in the development of neural tissues, particularly the eye. Activity of this protein is also required for expression of glucagon in the pancreas. This gene is regulated by multiple enhancers located up to tens or hundreds of kilobases upstream and downstream of the transcription start sites. Mutations in this gene or deletion of these regulatory elements results in severe defects in eye development. Alternative splicing and the use of alternative promoters results in multiple transcript variants, some of which encode proteins that lack the N-terminal paired domain. [provided by RefSeq, Jul 2015]
PHENOTYPE: Null and hypomorphic mutants show a range of phenotypes from viable with small eyes and lens/cornea fusion to microphthalmia and cataract to embryonic or perinatal lethality with anophthalmia and severe craniofacial and forebrain defects. [provided by MGI curators]
|
| Allele List at MGI |
|
| Other mutations in this stock |
Total: 67 list
| Gene | Ref | Var | Chr/Loc | Mutation | Predicted Effect | Zygosity |
|---|
| Ahnak |
A |
G |
19: 8,995,641 (GRCm39) |
I5642V |
probably benign |
Het |
| Atp5f1a |
A |
G |
18: 77,866,930 (GRCm39) |
|
probably null |
Het |
| Bltp1 |
T |
A |
3: 36,985,260 (GRCm39) |
N863K |
probably benign |
Het |
| Bsn |
A |
T |
9: 107,990,453 (GRCm39) |
F1766L |
probably damaging |
Het |
| Ccdc141 |
T |
C |
2: 76,938,807 (GRCm39) |
Q266R |
probably damaging |
Het |
| Cdh10 |
T |
A |
15: 18,964,154 (GRCm39) |
D105E |
possibly damaging |
Het |
| Clca3a1 |
T |
A |
3: 144,455,539 (GRCm39) |
D418V |
probably damaging |
Het |
| Cnnm2 |
C |
A |
19: 46,845,344 (GRCm39) |
T612K |
probably benign |
Het |
| Col3a1 |
T |
C |
1: 45,360,735 (GRCm39) |
V55A |
unknown |
Het |
| Cpd |
A |
C |
11: 76,737,097 (GRCm39) |
D232E |
probably benign |
Het |
| Csde1 |
A |
G |
3: 102,947,333 (GRCm39) |
H95R |
probably benign |
Het |
| Ctcfl |
T |
A |
2: 172,937,130 (GRCm39) |
H596L |
probably benign |
Het |
| Cwc22 |
T |
C |
2: 77,726,515 (GRCm39) |
R855G |
possibly damaging |
Het |
| Cwc25 |
A |
G |
11: 97,644,053 (GRCm39) |
Y227H |
probably damaging |
Het |
| Cyp2c38 |
G |
A |
19: 39,380,659 (GRCm39) |
P409S |
probably damaging |
Het |
| Ddx5 |
A |
G |
11: 106,679,139 (GRCm39) |
S2P |
possibly damaging |
Het |
| Dnah2 |
C |
A |
11: 69,348,238 (GRCm39) |
G2570W |
probably damaging |
Het |
| Dnajc10 |
T |
A |
2: 80,174,292 (GRCm39) |
V528E |
probably damaging |
Het |
| Efcab3 |
G |
A |
11: 104,810,312 (GRCm39) |
D3150N |
unknown |
Het |
| Fmo1 |
A |
G |
1: 162,677,629 (GRCm39) |
|
probably null |
Het |
| Gpatch1 |
C |
A |
7: 35,002,848 (GRCm39) |
D221Y |
probably damaging |
Het |
| Ino80 |
T |
C |
2: 119,213,895 (GRCm39) |
Y1225C |
probably damaging |
Het |
| Itga7 |
T |
A |
10: 128,779,955 (GRCm39) |
D501E |
probably benign |
Het |
| Lgr4 |
T |
C |
2: 109,842,243 (GRCm39) |
S743P |
possibly damaging |
Het |
| Lilra5 |
A |
T |
7: 4,241,360 (GRCm39) |
Y99F |
probably damaging |
Het |
| Lmna |
A |
G |
3: 88,410,265 (GRCm39) |
V49A |
probably damaging |
Het |
| Lrrc72 |
G |
A |
12: 36,258,603 (GRCm39) |
R267* |
probably null |
Het |
| Mapkbp1 |
T |
C |
2: 119,853,772 (GRCm39) |
S1199P |
probably damaging |
Het |
| Mmp25 |
G |
A |
17: 23,849,768 (GRCm39) |
A541V |
possibly damaging |
Het |
| Myh10 |
A |
T |
11: 68,701,058 (GRCm39) |
N1756Y |
probably damaging |
Het |
| Nfe2 |
A |
G |
15: 103,159,378 (GRCm39) |
I31T |
probably damaging |
Het |
| Nfe2l1 |
A |
T |
11: 96,708,570 (GRCm39) |
F732I |
probably benign |
Het |
| Or4a39 |
C |
G |
2: 89,237,074 (GRCm39) |
M116I |
possibly damaging |
Het |
| Or4c12b |
T |
A |
2: 89,647,104 (GRCm39) |
C145S |
probably damaging |
Het |
| Or52e19b |
C |
A |
7: 103,032,403 (GRCm39) |
V269F |
possibly damaging |
Het |
| Phb1 |
A |
G |
11: 95,568,941 (GRCm39) |
E192G |
probably damaging |
Het |
| Plekhn1 |
A |
T |
4: 156,309,650 (GRCm39) |
|
probably null |
Het |
| Plxnb2 |
A |
T |
15: 89,046,189 (GRCm39) |
V942E |
probably damaging |
Het |
| Potegl |
T |
A |
2: 23,156,745 (GRCm39) |
|
probably benign |
Het |
| Rsrc2 |
G |
A |
5: 123,877,751 (GRCm39) |
|
probably benign |
Het |
| Septin8 |
G |
A |
11: 53,439,210 (GRCm39) |
C460Y |
probably benign |
Het |
| Slc13a2 |
CGTTATCTGT |
CGT |
11: 78,294,306 (GRCm39) |
|
probably benign |
Het |
| Slc16a7 |
A |
G |
10: 125,130,508 (GRCm39) |
I59T |
probably benign |
Het |
| Slc35d1 |
A |
T |
4: 103,065,365 (GRCm39) |
I172N |
possibly damaging |
Het |
| Smg5 |
A |
T |
3: 88,249,208 (GRCm39) |
N40Y |
possibly damaging |
Het |
| Smurf1 |
A |
G |
5: 144,818,541 (GRCm39) |
V633A |
probably damaging |
Het |
| Snx9 |
T |
C |
17: 5,937,324 (GRCm39) |
V22A |
probably damaging |
Het |
| Sox6 |
A |
T |
7: 115,076,295 (GRCm39) |
M741K |
probably damaging |
Het |
| Spata31d1d |
T |
C |
13: 59,873,797 (GRCm39) |
Q1246R |
probably benign |
Het |
| Sval1 |
A |
G |
6: 41,928,660 (GRCm39) |
E24G |
probably damaging |
Het |
| Tas2r124 |
A |
G |
6: 132,731,867 (GRCm39) |
I59V |
probably benign |
Het |
| Tmem151b |
T |
A |
17: 45,857,992 (GRCm39) |
T85S |
probably benign |
Het |
| Tpr |
T |
A |
1: 150,317,996 (GRCm39) |
|
probably null |
Het |
| Trpm6 |
A |
C |
19: 18,831,472 (GRCm39) |
T1446P |
possibly damaging |
Het |
| Tsc22d4 |
A |
T |
5: 137,766,441 (GRCm39) |
K502N |
possibly damaging |
Het |
| Tssk3 |
C |
T |
4: 129,383,051 (GRCm39) |
S207N |
probably benign |
Het |
| Ttbk1 |
G |
T |
17: 46,778,188 (GRCm39) |
P618Q |
probably damaging |
Het |
| Ttll6 |
A |
T |
11: 96,047,371 (GRCm39) |
M657L |
probably benign |
Het |
| Ubash3a |
T |
A |
17: 31,434,069 (GRCm39) |
I138N |
probably benign |
Het |
| Ush2a |
A |
G |
1: 188,090,839 (GRCm39) |
Y490C |
probably damaging |
Het |
| Vmn1r82 |
G |
T |
7: 12,039,461 (GRCm39) |
V127F |
probably damaging |
Het |
| Vmn2r32 |
A |
T |
7: 7,479,691 (GRCm39) |
S161T |
possibly damaging |
Het |
| Wdr49 |
T |
C |
3: 75,388,824 (GRCm39) |
I58M |
possibly damaging |
Het |
| Wiz |
A |
T |
17: 32,579,417 (GRCm39) |
|
probably null |
Het |
| Wrap53 |
A |
T |
11: 69,453,619 (GRCm39) |
Y324* |
probably null |
Het |
| Zfp747 |
A |
C |
7: 126,975,138 (GRCm39) |
|
probably benign |
Het |
| Zfp827 |
A |
G |
8: 79,905,702 (GRCm39) |
Y33C |
probably damaging |
Het |
|
| Other mutations in Pax6 |
| Allele | Source | Chr | Coord | Type | Predicted Effect | PPH Score |
|---|
|
IGL02008:Pax6
|
APN |
2 |
105,522,623 (GRCm39) |
critical splice donor site |
probably null |
|
|
IGL02256:Pax6
|
APN |
2 |
105,515,115 (GRCm39) |
missense |
probably benign |
0.16 |
|
IGL02500:Pax6
|
APN |
2 |
105,523,115 (GRCm39) |
missense |
probably benign |
0.13 |
|
beady
|
UTSW |
2 |
105,522,036 (GRCm39) |
missense |
probably damaging |
1.00 |
|
red_hots
|
UTSW |
2 |
105,525,705 (GRCm39) |
missense |
probably benign |
0.00 |
|
G1citation:Pax6
|
UTSW |
2 |
105,516,268 (GRCm39) |
missense |
probably benign |
0.04 |
|
R1067:Pax6
|
UTSW |
2 |
105,510,646 (GRCm39) |
missense |
probably benign |
0.01 |
|
R1213:Pax6
|
UTSW |
2 |
105,516,258 (GRCm39) |
missense |
probably benign |
0.13 |
|
R1494:Pax6
|
UTSW |
2 |
105,521,955 (GRCm39) |
missense |
probably benign |
0.16 |
|
R1633:Pax6
|
UTSW |
2 |
105,522,063 (GRCm39) |
missense |
probably damaging |
1.00 |
|
R2291:Pax6
|
UTSW |
2 |
105,516,228 (GRCm39) |
missense |
probably benign |
0.09 |
|
R3834:Pax6
|
UTSW |
2 |
105,526,795 (GRCm39) |
missense |
probably benign |
0.00 |
|
R3835:Pax6
|
UTSW |
2 |
105,526,795 (GRCm39) |
missense |
probably benign |
0.00 |
|
R4665:Pax6
|
UTSW |
2 |
105,514,343 (GRCm39) |
intron |
probably benign |
|
|
R4714:Pax6
|
UTSW |
2 |
105,525,745 (GRCm39) |
missense |
possibly damaging |
0.74 |
|
R4747:Pax6
|
UTSW |
2 |
105,526,847 (GRCm39) |
missense |
probably benign |
|
|
R4764:Pax6
|
UTSW |
2 |
105,526,847 (GRCm39) |
missense |
probably benign |
|
|
R4767:Pax6
|
UTSW |
2 |
105,525,705 (GRCm39) |
missense |
probably benign |
0.00 |
|
R4771:Pax6
|
UTSW |
2 |
105,526,847 (GRCm39) |
missense |
probably benign |
|
|
R4772:Pax6
|
UTSW |
2 |
105,526,847 (GRCm39) |
missense |
probably benign |
|
|
R4816:Pax6
|
UTSW |
2 |
105,514,129 (GRCm39) |
intron |
probably benign |
|
|
R4819:Pax6
|
UTSW |
2 |
105,522,622 (GRCm39) |
critical splice donor site |
probably null |
|
|
R5418:Pax6
|
UTSW |
2 |
105,521,910 (GRCm39) |
missense |
probably benign |
0.00 |
|
R5683:Pax6
|
UTSW |
2 |
105,516,252 (GRCm39) |
missense |
probably benign |
0.06 |
|
R6041:Pax6
|
UTSW |
2 |
105,514,247 (GRCm39) |
missense |
probably damaging |
1.00 |
|
R6651:Pax6
|
UTSW |
2 |
105,516,175 (GRCm39) |
missense |
probably benign |
0.00 |
|
R6822:Pax6
|
UTSW |
2 |
105,516,268 (GRCm39) |
missense |
probably benign |
0.04 |
|
R7042:Pax6
|
UTSW |
2 |
105,526,718 (GRCm39) |
missense |
probably benign |
|
|
R7088:Pax6
|
UTSW |
2 |
105,526,753 (GRCm39) |
missense |
probably benign |
0.00 |
|
R7102:Pax6
|
UTSW |
2 |
105,522,604 (GRCm39) |
missense |
probably damaging |
0.98 |
|
R7294:Pax6
|
UTSW |
2 |
105,515,246 (GRCm39) |
nonsense |
probably null |
|
|
R7761:Pax6
|
UTSW |
2 |
105,522,036 (GRCm39) |
missense |
probably damaging |
1.00 |
|
R7948:Pax6
|
UTSW |
2 |
105,516,222 (GRCm39) |
missense |
probably benign |
|
|
R8882:Pax6
|
UTSW |
2 |
105,521,963 (GRCm39) |
missense |
possibly damaging |
0.96 |
|
R9151:Pax6
|
UTSW |
2 |
105,523,097 (GRCm39) |
missense |
probably benign |
0.10 |
|
R9796:Pax6
|
UTSW |
2 |
105,522,541 (GRCm39) |
missense |
probably damaging |
1.00 |
|
Z1177:Pax6
|
UTSW |
2 |
105,516,161 (GRCm39) |
missense |
possibly damaging |
0.64 |
|
| Predicted Primers |
PCR Primer
(F):5'- TTGCCTTGTAATGAATGACCTTGC -3'
(R):5'- AGGCACATTAACTTGACTGAACAG -3'
Sequencing Primer
(F):5'- GTAATGAATGACCTTGCCCTCTC -3'
(R):5'- GGGCATGAATCAATCAATCAGTC -3'
|
| Posted On |
2018-03-15 |
Incidental Mutation