Preferential insert orientation

Paul N Hengen pnh at
Wed Dec 29 15:39:27 EST 1993

In article <gregoryh-271293155836 at>
gregoryh at (Gregory R. Harriman) writes:

> What can cause inserts with the same restriction site on both ends to
> ligate in only one direction? Any advice or helpful suggestions would be
> appreciated!

1. Secondary structure of the DNA fragments may prohibit the ligation in one
particular orientation, ie., one end of each molecule is much more frequently
ligated first.

2. The transformants of both types of molecules are never seen because the
insert may be expressed from a vector promoter in only one orientation and the
product(s) are lethal to the cell.

* Paul N. Hengen, Ph.D.                           /--------------------------/*
* National Cancer Institute                       |Internet: pnh at |*
* Laboratory of Mathematical Biology              |   Phone: (301) 846-5581  |*
* Frederick Cancer Research and Development Center|     FAX: (301) 846-5598  |*
* Frederick, Maryland 21702-1201 USA              /--------------------------/*

More information about the Methods mailing list