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Table 2 Possible changes in MSAP MH profiles from Figure 1 and their interpretation

From: How to interpret Methylation Sensitive Amplified Polymorphism (MSAP) profiles?

Plants

1MH1 → MH2

methylation change

MSAP pattern (Figure 1)

7interpretation

2(-, -) → (+, +)

3s(mCmC → CC)

4S5(4 → 1)

ambiguous

 

6s(mCmC → CC) and l(CmC → CC)

S(5 → 1)

 
 

s(CC → mCmC)

L(1 → 4)

 
 

s(CmC → mCmC) and l(CmC → CC)

L(3 → 4)

 

(-, -) → (+, -)

s(mCmC → CmC)

S(4 → 2) or S(5 → 3)

ambiguous

 

s(mCmC → CmC) and l(CC → CmC)

S(4 → 3)

 
 

s(mCmC → CmC) and l(CmC → CC)

S(5 → 2)

 
 

s(CmC → mCmC)

L(3 → 5)

 
 

s(CC → mCmC) and l(CC → CmC)

L(1 → 5)

 

(-, -) → (-, +)

l(CmC → CC)

L(3 → 2)

ambiguous

 

s(CC → CmC)

L(1 → 2)

 

(+, +) → (-, -)

s(CC → mCmC)

S(1 → 4)

ambiguous

 

s(CC → mCmC) and l(CC → CmC)

S(1 → 5)

 
 

s(mCmC → CC)

L(4 → 1)

 
 

s(mCmC → CmC) and l(CC → CmC)

L(4 → 3)

 

(+, +) → (+, -)

s(CC → CmC)

S(1 → 2)

methylation

 

s(CC → CmC) and l(CC → CmC)

S(1 → 3)

 
 

l(CC → CmC)

L(4 → 5)

 

(+, +) → (-, +)

s(mCmC → CmC)

L(4 → 2)

hypomethylation

(+, -) → (-, -)

s(CmC → mCmC)

S(2 → 4) or S(3 → 5)

ambiguous

 

s(CmC → mCmC) and l(CC → CmC)

S(2 → 5)

 
 

s(CmC → mCmC) and l(CmC → CC)

S(3 → 4)

 
 

s(mCmC → CmC)

L(5 → 3)

 
 

s(mCmC → CC) and l(CmC → CC)

L(5 → 1)

 

(+, -) → (+, +)

s(CmC → CC)

S(2 → 1)

hypomethylation

 

s(CmC → CC) and l(CmC → CC)

S(3 → 1)

 
 

l(CmC → CC)

L(5 → 4)

 

(+, -) → (-, +)

s(mCmC → CmC) and l(CmC → CC)

L(5 → 2)

hypomethylation

(-, +) → (-, -)

s(CmC → CC)

L(2 → 1)

ambiguous

 

l(CC → CmC)

L(2 → 3)

 

(-, +) → (+, +)

s(CmC → mCmC)

L(2 → 4)

methylation

(-, +) → (+, -)

s(CmC → mCmC) and l(CC → CmC)

L(2 → 5)

methylation

Vertebrates

MH1 → MH2

sequence change

MSAP pattern (Figure 1)

interpretation

(-, -) → (+, +)

8new CCGG

-

mutation

(-, -) → (+, -)

new CmCGG

-

mut. + met.

(-, -) → (-, +)

l(CmC → CC)

L(3 → 2)

ambiguous

 

s(CC → CmC)

L(1 → 2)

 

(+, +) → (-, -)

CCGG loss

-

mutation

(+, +) → (+, -)

s(CC → CmC)

S(1 → 2)

methylation

(+, +) → (-, +)

new internal CmCGG

-

mut. + met.

(+, -) → (-, -)

CmCGG loss

-

mutation

 

new internal CmCGG

-

 

(+, -) → (+, +)

s(CmC → CC)

S(2 → 1)

hypomethylation

 

s(CmC → CC) and l(CmC → CC)

S(3 → 1)

 

(+, -) → (-, +)

(CmC → CC) and new int. CmCGG

-

mutation

(-, +) → (-, -)

s(CmC → CC)

L(2 → 1)

ambiguous

 

l(CC → CmC)

L(2 → 3)

 

(-, +) → (+, +)

internal CmCGG loss

-

mutation

(-, +) → (+, -)

(CC → CmC) and int. CmCGG loss

-

mutation

  1. 1MH1 and MH2 represent the original (control) and a changed MSAP profile, respectively.
  2. 2- and + in parentheses denote the absence and the presence of a band in MspI (M) and HpaII (H) lanes.
  3. 3s and l indicate restriction sites in Figure 1 (the "methylation change" and "sequence change" columns).
  4. 4S and L indicate specific MSAP fragments (the "MSAP pattern column") according their lengths from Figure 1.
  5. 5The numbers in parenthesis correspond to the methylation states of the sequence and the MSAP profiles in Figure 1.
  6. 6Some MSAP profile changes are explained by two methylation changes (both s and l MspI/HpaII sites).
  7. 7Interpretation for each MH1→MH2 profile change is noted in the interpretation column.
  8. 8Majority of possible MSAP profile changes in vertebrates are explained by gain or loss of the restriction site and therefore are expected to be very rare.