Out of the Blue

GenomicsOne's TrueBlue Cloning Scheme For the past two decades, cloners have relied on lacZ*-based color selection vectors to identify cloned inserts. These systems are based on the insertional inactivation of the lacZ* gene fragment and are (deceptively) simple. The lacZ gene encodes the ß-galactosidase (ßGal) protein, which acts on an indicator substrate to produce blue colonies. Thus, in a cloning experiment, white colonies indicate that the DNA of interest has been inserted into t

Written byAileen Constans

| 2 min read

Save for Later

Listen with Speechify

0:00

2:00

GenomicsOne's TrueBlue Cloning Scheme

For the past two decades, cloners have relied on lacZ*-based color selection vectors to identify cloned inserts. These systems are based on the insertional inactivation of the lacZ* gene fragment and are (deceptively) simple. The lacZ gene encodes the ß-galactosidase (ßGal) protein, which acts on an indicator substrate to produce blue colonies. Thus, in a cloning experiment, white colonies indicate that the DNA of interest has been inserted into the lacZ* coding region of the vector, disrupting ßGal expression, while blue colonies indicate that lacZ is intact and insertion has not occurred. However, many blue-white screeners find that this color selection method can be quite inaccurate, and one study found that approximately 30-40 percent of blue colonies actually contained inserts.¹GenomicsOne Corp. of Montreal has come to the rescue with its TrueBlue Technology, which provides a highly reliable blue-white selection procedure.

False negatives can occur when ...

Interested in reading more?

Become a Member of

Receive full access to digital editions of The Scientist, as well as TS Digest, feature stories, more than 35 years of archives, and much more!

Join for free today

Already a member?