Pisum Genetics 

Volume 26

1994

Research Reports

pages 24-25

Futher evidence that the mutant Fix gene in line Sprint-2Fix- is in pea linkage group III

Rozov, S.M.1, Borisov, A.Y.2 and Tsyganov, V.E.2 

 

 

 1Institute of Cytology and Genetics

Novosibirsk , 630090, Russia

2Research Institute for Agricultural Microbiology

Podbelsky Shosse 3, St Petersburg-Pushkin 8, 189620,  Russia

In a previous paper (2) we reported that the gene for our new Sprint-2Fix- mutant (1) was linked to the group III gene M with a recombination frequency of 21.4 7.7%. Allelism tests are still incomplete, but the mutant gene will be identified in due course by a numbered symbol in the Sym series. To locate the new gene more precisely, two further crosses were made involving additional group III markers. The F2 data for cross NGB851 (m, st, Fix+) x Sprint-2Fix- (M, St, Fix-) indicate the new gene is located between loci M and St (Table 1). Significant linkage (P<0.0001) occurred with both markers. The F2 data for cross SGE656 (m, unitac Fix+) x Sprint-2Fix- (M, Uni, Fix-) indicate the new gene is located below uni in the direction of st (Table 2). The linkage with uni is significant at the 0.0001 level.

With help of the computer mapping program JOINMAP (3), the data from the two crosses were combined to produce the following map of the M to st region of linkage group III, The distances in this map are given in cM (the Kosambi function was used).

 

Table 1. F2 segregation data from cross NGB851 (m, st, Fix+) x Sprint-2Fix- (M, St, Fix-).

 

Phenotype1

Joint Chi-sq

Recomb frac

SE

Loci

A/B

A/h

A/b

h/B

h/h

h/b

a/B

a/h

a/b

M

Fix

18

40

13

 

 

 

2

6

23

29.57**

21.1

4.5

St

Fix

16

8

1

9

26

4

11

12

15

26.93**

32.9

4.2

M

St

28

29

14

 

 

 

10

10

11

2.90

43.6

6.0

A,a - first gene; B,b - second gene; h - heterozygous. When the second gene was treated as codominant, capital A stands for the dominant allele of the first gene and capital B for an allele of the second gene, being in coupling with A. When both genes were treated as codominant, a capital letter stands for an allele of the first parent.

** P< 0.0001.

Table 2. F2 segregation data from cross SGE656 (m, unitac Fix+) x Sprint-2Fix- (M, Uni, Fix-).

 

 

Phenotype1

Joint
Chi-sq

Recomb
frac

SE

Loci

A/B

A/h

A/b

h/B

h/h

h/b

a/B

a/h

a/b

Uni

M

24

2

5

5

10

4

0

2

15

47.45**

17.84

3.71

Uni

Fix

20

5

5

2

7

8

0

4

9

25.09**

25.38

4.76

M

Fix

16

6

5

2

6

5

2

4

12

17.73*

28.09

5.13

1 See Table 1 footnote.

*P<0.01, **P<0.0001.

Acknowledgements. This work was supported financially by Research Program INTERBIOAZOT and partially funded by the National Program Frontiers in Genetics, Russian Fund of Fundamental Investigations and International Science Foundation (Soros).

  1. Borisov, A.Y., Morzina, E.V., Kulikova, O.A., Tchetkova, S.A., Lebsky, V.K. and
    Tikhonovich, I.A. 1992. Symbiosis 14:297-313.

  2. Rozov, S.M., Borisov, A.Y., Tsyganov, V.E. and Tikhonovich, I.A. 1993. Pisum
    Genetics 25:45.

  3. Stamm, P. 1993. The Plant Journal 5:739-744.