Table 1

Distribution of syntenic block sizes (≥3 genes) at the root of the Drosophila tree under various relaxed criteria

No. of blocks

Syntenic block size (no. of genes)

Criterion 1

Criterion 2

Criterion 3

3

283

279

162

4

119

113

57

5

137

136

67

6

86

82

52

7

73

71

55

8

54

59

53

9

34

30

29

10

39

35

33

11

36

33

27

12

26

28

19

13

22

23

28

14

22

24

27

15

16

15

18

16

11

13

14

17

9

12

10

18

9

10

9

19

6

5

7

20

7

7

9

21

6

5

7

22

5

5

7

23

1

3

6

24

4

4

6

25

2

2

4

26

4

4

5

27

2

2

6

28

2

2

2

29

4

3

5

30

1

2

4

31

0

1

5

32

3

2

5

33

2

3

2

35

0

0

2

36

1

1

2

38

0

0

1

39

1

1

1

40

1

1

2

41

0

1

1

43

0

0

1

44

0

0

1

46

0

0

1

47

0

0

2

48

1

1

1

51

0

0

1

54

0

0

1

61

0

0

1

Note that criterion 2 is weaker than criterion 1 and criterion 3 includes the weakest assumptions. Criterion 1: first-pass syntenic blocks. Criterion 2: result of bridging syntenic blocks with genes on block edges paired using outgroup species evidence. Criterion 3: further merging of syntenic blocks based on relaxed assumption of bridging blocks using genes on block edges paired in at least one fly species. See Additional data files 6 and 7 for gene composition of blocks.

Bhutkar et al. Genome Biology 2007 8:R236   doi:10.1186/gb-2007-8-11-r236