Reply: Human germline genetic modification: Scientific and bioethical perspectives

摘要

We thank Dr. Horacio Rivera for his response to our article. In reply, we wish to make the following points.1. The premise stated by Dr. Horacio Rivera, to the effect that connections between genotype and phenotype are often highly complex and frequently subject to modification by environmental factors, is indubitable. Nevertheless, it is also true that the fundamental biological makeup of any organism is established (during development) by the genetic sequences that constitute that organism's genome. This is true for all organisms, including humans. Thus, human features including longevity, cognitive function and physical attributes are in principle amenable to deliberate alteration by means of genetic modification. This is also true in practice: in the context of animal transgenesis, numerous experiments have demonstrated successful genetic manipulation of various physical and neural features in complex mammals. Moreover, although molecular genetics is at a relatively nascent stage, elucidations of genotype-phenotype links are beginning to emerge, even for complex (polygenic) traits and disorders. As the science progresses, greater knowledge of the influence of given sequences on phenotype will help to make human genetic improvement an increasingly realistic prospect.