Adaptive mutation is defined as a process that, during nonlethal selections, produces mutations that relieve the selective pressure whether or not other, nonselected mutations are also produced. Examples of adaptive mutation or related phenomena have been reported in bacteria and yeast but not yet outside of microorganisms. A decade of research on adaptive mutation has revealed mechanisms that may increase mutation rates under adverse conditions. This article focuses on mechanisms that produce adaptive mutations in one strain of Escherichia coli, FC40. (...) These mechanisms include recombination-induced DNA replication, the placement of genes on a conjugal plasmid, and a transient mutator state. The implications of these various phenomena for adaptive evolution in microorganisms are discussed. BioEssays 22:1067–1074, 2000. © 2000 John Wiley & Sons, Inc. (shrink)

Questions concerning the moral status of embryos, the validity of new technologies for human reproduction, ownership of one's own genes, gene patenting, privacy and discrimination have all been raised and debated. Although debate is healthy, it is only useful if all participants understand the fundamental biological principles underlying human life, human genes and human parenthood. Many people believe that science can play no role in determining when human life begins. I argue that this false assumption is based on a failure (...) to separate different contradictory meanings of the term ‘human life’. In actuality, science has provided great insight into when and how human life and human beings come into existence. I argue as well that, contrary to our intuitive feelings, there is no physical connection between any father and his son; shared genes represent shared information and nothing more. Nevertheless, the feeling of a physical connection between parent and child is very real and instinctive, no matter how false it may be. These new understandings have profound ramifications for the way we treat issues surrounding human reproduction, including both abortion and assisted reproductive technologies. (shrink)

In 1970, Jacque Monod, a Nobel Laureate and a founding father of molecular biology, wrote a short celebrated book entitled Chance and Necessity.

On Sunday morning, 23 February 1997, the world awoke to a technological advance that shook the foundations of biology and philosophy. On that day, we were introduced to Dolly, a 6-month-old lamb that had been cloned directly from a single cell taken from the breast tissue of an adult donor. Perhaps more astonished by this accomplishment than any of their neighbors were the scientists who actually worked in the field of mammalian genetics and embryology. Outside the lab where the cloning (...) had actually taken place, most of us thought it could never happen. Oh, we would say that perhaps at some point in the distant future, cloning might become feasible through the use of sophisticated biotechnologies far beyond those available to us now. But what many of us really believed, deep in our hearts, was that this was one biological feat we could never master. New lifemust have its origins in an embryo formed through the merger of gametes from a mother and father. It was impossible, we thought, for a cell from an adult mammal to become reprogrammed, to start all over again, to generate another entire animal or person in the image of the one born earlier. (shrink)

The discovery, more than 60 years ago, of a mutant mouse with a short tail led to the birth of the new field of developmental genetics. Over the years since, numerous investigators have probed the biology of the original short‐tail mutation at the T locus, as well the naturally‐occurring t haplotypes that were uncovered as a result of their interaction with this mutation. Although the T locus ranks among the best characterized developmental loci in the mouse, it was not among (...) the first to be cloned. This situation has now been rectified with two recent reports from Herrmann, Lehrach and their colleagues. While the T locus is expressed uniquely in the embryonic tissues predicted from the mutant phenotype, the gene itself, as well as the predicted amino acid sequence of the T product, show no strong homology to any known sequence. For the moment, at least, the mystery behind the function of the T locus still awaits definitive resolution. (shrink)

In this paper I will discuss three areas in which advances in human reproductive technology could occur, their uses and abuses, and their effects on society. First is the potential to drastically increase the success rate and availability of in vitro fertilization and embryo freezing. Second is the ability to perform biopsies on embryos prior to the onset of pregnancy. Finally, I will consider the adding or altering of genes in embryos, commonly referred to as genetic engineering.As new reproductive technologies (...) pass from experimental models into the potential for medical utilization, I believe that it will be important for lawmakers everywhere to avoid the impulse to outlaw procedures that a society believes to be unnatural at a first glance. Rather, I would hope that they can respond thoughtfully with legislation that serves two purposes — to protect the rights of couples to overcome infertility or to reduce the risk of genetic disease in their children-to-be, and more importantly, to protect children-to-be from the abuses that could result from some of the practices that I will discuss. (shrink)