PNL Volume 17

1985

RESEARCH REPORTS

A REVISED LINKAGE MAP OF CHROMOSOME 5 IN PISUM

Folkeson, D.

Institute of Genetics, University of Lund

Solvegatan, Lund, Sweden

Further analysis for the orientation of linkage group V has been

carried out by the use of tertiary trisomies and linkage analysis, as

recommended by Lamm (6). Mitotic measurements by Blixt (1) have clearly

shown that L-379 is a T(3S-5L) interchange. L-379 and L-83 have appa-

rently the same origin and have been shown to be structurally identical

by Lamm (5). Analysis of tertiary trisomies and of linkage relations of

L-83 has been performed by Lamm (4). The junction of linkage group V and

VII as previously proposed by Lamm (4, 7) has elicited some discussions.

Linkage analysis has shown free segregation between the interchange point

of Merton I (3Sp-7Sp) and gene markers wsp, tl^w, r, bt (3). In the

latter paper, the location of the "linkage sequence" VII in the distal

part in the long arm of chromosome 5 is thoroughly discussed (cf.

Fig..l). The junction of two linkage groups is, however, not so remark-

able, a similar situation having been recorded in barley (2). The inver-

sion of linkage sequence V in chromosome 5 has previously been pointed

out by Lamm (6). To extend his analysis, I have performed the following

cross:

L-83 x L-1458 (Gp_, Ce, Fs, T[3S-5L] x gp_, ce, fs, N-type.)

The result of this cross (Table la) reveals the following linkage rela-

tion:

Fs - 1.6% - Ce - 19.6% - T - 13.8% - Gp

A compilation of previous cytogenetic measurements by Blixt (1), analyses

of tertiary trisomies by Lamm (8), and the values presented here (Table

lb) place the gene marker gp at 5L and thus ce most probably at 5S.

Detailed arguments for this will be published in Hereditas.

Fig. 1. Linkage relation in chromosome 5 (c=centromere).

1. Blixt, S. 1959. Agri Hort. Genet. 17:47-75.

2. Burnham, C. R. and A. Hagberg. Hereditas 42:467-482.

3. Folkeson, D. 1984. Hereditas 101:227-233.

4. Lamm, R. 1951. Hereditas 37:356-372.

5. Lamm, R. 1974. PNL 6:19.

6. Lamm, R. 1977. PNL 9:26-27.

7. Lamm, R. 1978. PNL 10:32-33.

8. Lamm, R. and R. J. Miravalle. 1959. Hereditas 15:417-440.

PNL Volume 17 1985

RESEARCH REPORTS 15

Table la. Crosses performed between L-83 and lines of normal structural

__type.__

Cross Parental lines_Genotype and karyotype_References

A L-83 x L-44 Gp, T(3S-5L) x gp, N-type PNL 9:26-27

B L-83 x L-1072 Gp, T(3S-5L) x gp, N-type Lamm (unpub.)

C L-83 x L-1458 Gp, T(3S-5L) x gp, N-type Current values

Table lb. Frequency, in crosses listed in Table la, of various types

of trisomies carrying the interchange chromosomes (3⁵) long

or (5³) short, respectively, in addition to the normal

karyotype.