Why the White colonies in the blue/white screening of E.coli with pUC-18 vector appear bigger than the blue colonies?

Monoswi Chakraborty @Monoswi-Chakraborty

30 October 2021 0 7K Report

I am performing a cloning experiment of a plasmodium gene with pUC-18 vector in E.coli (strain DH5alpha). After ligation when I am trying to analyze my vector+insert plate (X-gal+IPTG+LB-Amp), I am seeing bigger white colonies and very small blue colonies. I understand the appearance of white colonies is probably due to issues in transformation efficiency but why is there size difference between the blue and white colonies. Technically there shouldn't be, right?

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