ALTER CONSTRAINT FOREIGN KEY

Question,

When I created a TABLE clone I initially defined a column:
gb_accessions_id INTEGER REFERENCES gb_accessions(gb_accessions_id) NULL

I have renamed TABLE gb_accessions to TABLE gb, and its column
gb_accessions_id to gb_id.

I next renamed the column 'gb_accessions_id' in TABLE clone to 'gb_id'.
In renaming this column in TABLE clone I appear to have lost the
reference to TABLE gb (see below).

Questions:

1. During which step in my renaming did this occur?
2. How should I have carried this out?
3. Can I add back REFERENCES gb(gb_id)?

Database chlamy_est - Table clone

Field Type LengthNot Null Default
clone_id int4 4 Yes nextval('"clone_clone_id_seq"'::text)
project int4 4 Yes
plate int4 4 Yes
row char 1 Yes
col int4 4 Yes
read char 1 Yes
ver int4 4 Yes
seq text var Yes
qual text var Yes
length int4 4 Yes
qual_length int4 4 Yes
mean_qual_after_trim int4 4 Yes
qual_start int4 4 Yes
qual_end int4 4 Yes
comment text var Yes
gb_id int4 4 No

Keyname Unique Primary Field
clone_pkey Yes Yes clone_id
clone_project_key Yes No col
clone_project_key Yes No plate
clone_project_key Yes No project
clone_project_key Yes No read
clone_project_key Yes No row
clone_project_key Yes No ver

Thanks.
--
Regards,

Chuck