1. A viable pale green character easily classifiable as seedling and up to time of flowering was found in an F2 population in a 3:1 ratio. Subsequent tests showed that this character is due to duplicate genes. One of these genes is in chromosome 6. The following data were obtained:

 

B. C. for Y and Pl and for the two pg genes

 

Y

y

Y

y

Y

y

Y

y

Pg

pg

pg

Pg

Pg

pg

pg

Pg

Pl

pl

pl

Pl

pl

Pl

Pl

pl

661

319

92

176

178

40

3

337

 

From these data the linear order and recombination values are:

 

Y‑‑20.9‑‑Pg‑‑9.5‑‑Pl

 

In one family the pg gene not in chromosome 6 was homozygous and a B.C. ratio of one green to one pale green was found. These data are:

 

Y

y

Y

y

Y

y

Y

y

Pg

pg

pg

Pg

Pg

pg

pg

Pg

Pl

pl

pl

Pl

pl

Pl

Pl

pl

128

93

32

23

27

11

3

1

 

Here the linear order is as above but slightly different recombination values were obtained:

 

Y‑Pg 18.6

Pg‑Pl 13.2