Forbidden knowledge. A case study with commentaries exploring ethical issues and genetic research.

This case is part of a series of case studies used as an exercise within a program on research ethics education. The case involves research on genetic birth defects in a culturally distinct, closed religious community in which elders speak for the community. The case raises ethical issues of informed consent in such a setting; of collaboration with the community; of conflicts between the researchers' responsibilities to the community as a whole and to individual subjects; of the impact of the researcher's findings on the practices and values of the community and issues regarding how the researchers share findings with subjects and how the findings are stored.

A detailed restriction endonuclease site map of theZea mays plastid genome.

Fragments produced by partial digestion of plastid DNA fromZea mays withEco RI were cloned in Charon 4A. A circular, fine structure physical map of the plastid DNA was then constructed from restriction endonucleaseSal I,Pst I,Eco RI, andBam HI recognition site maps of cloned overlapping segments of the plastid genome. These fragments were assigned molecular weights by reference to size markers from both pBR322 and lambda phage DNA.

A unified mechanism for the nuclease and unwinding activities of the recBC enzyme of Escherichia coli.

Using a gentle method to prepare complexes of duplex DNA and the recBC enzyme for electron microscopy, structures not seen previously were observed to be associated with the double strand DNA exonuclease activity of the enzyme. These were terminal forms and loop + tail(s) structures. Both individual terminal single-stranded tails and single-stranded regions within duplexes were also observed.