ABSTRACT Many philosophers who wish to defend abortion, but who have become frustrated by the resistance of the personhood question to yield to any nonarbitrary solution welcomed Judith Thomson's ‘A defense of abortion.’Thomson argues that abortion is sometimes justifiable even if the foetus is a person. In this paper I argue that Thomson's argument is a defense of abortion, rather than merely extraction without death, only because of the current state of medical technology. Once the technology is in place to (...) extract foetuses while preserving their lives and to allow them to develop to full term outside the uterus, Thomson cannot defend the killing of the foetus. If she is right, however, a woman will still have the right to have a foetus extracted from her body. Finally, it is pointed out that the source of the problem with Thomson's argument is the major premise in most arguments for the permissibility of abortion: a woman's right to control her own body. If the defence of abortion is to entail a defence of the termination of the foetus, then this premise, understood as the right to remove an unwanted entity from one's body or the right to alter one's body as one wishes, simply will not do the trick. (shrink)

DNA joining enzymes play an essential role in the maintenance of genomic integrity and stability. Three mammalian genes encoding DNA ligases, LIG1, LIG3 and LIG4, have been identified. Since DNA ligase II appears to be derived from DNA ligase III by a proteolytic mechanism, the three LIG genes can account for the four biochemically distinct DNA ligase activities, DNA ligases I, II, III and IV, that have been purified from mammalian cell extracts. It is probable that the specific cellular roles (...) of these enzymes are determined by the proteins with which they interact. The specific involvement of DNA ligase I in DNA replication is mediated by the non‐catalytic amino‐terminal domain of this enzyme. Furthermore, DNA ligase I participates in DNA base excision repair as a component of a multiprotein complex. Two forms of DNA ligase III are produced by an alternative splicing mechanism. The ubiqitously expressed DNA ligase III‐α forms a complex with the DNA single‐strand break repair protein XRCC1. In contrast, DNA ligase III‐β, which does not interact with XRCC1, is only expressed in male meiotic germ cells, suggesting a role for this isoform in meiotic recombination. At present, there is very little information about the cellular functions of DNA ligase IV. (shrink)