In the not-too-distant future, gene therapy may be an option for the treatment and cure of some inherited disorders. What do you think are the most serious ethical issues that must be dealt with before human gene therapy is used on a large scale? Why do you think these issues are important?

'Bt maize'a. is resistant to various herbicides, making it practical to weed rice fields with those herbicides.b. contains transgenes that increase vitamin A content.c. includes bacterial genes that produce a toxin that reduces damage from insect pests.d. is a 'boron (B)-tolerant' transgenic variety of maize.

Plants are more readily manipulated by genetic engineering than are animals becausea. plant genes do not contain introns.b. more vectors are available for transferring recombinant DNA into plant cells.c. a somatic plant cell can often give rise to a complete plant.d. plant cells have larger nuclei.

Today, it is fairly easy to make transgenic plants and animals. What are some important safety and ethical issues raised by this use of recombinant DNA technology? What are some of the possible dangers of introducing genetically engineered organisms into the environment? What are some reasons for and against leaving decisions in these areas to scientists? To business owners and executives? What are some reasons for and against more public involvement? How might these decisions affect you? How do you think these decisions should be made?

Contrast technology with science. Give an example of each to illustrate the difference.

SCIENTIFIC THINKING Scientists investigate hypotheses using a variety of methods, depending on the circumstances behind the research. Human nutrition studies (such as those studying whether GMO foods have any health effects) are particularly problematic. Can you design a hypothetical human nutrition study to test whether GMO corn is less healthy than traditional corn? Can you identify real-world problems that may interfere with your design and confound your results?

The fruits of wild species of tomato are tiny compared with the giant beefsteak tomatoes available today. This difference in fruit size is almost entirely due to the larger number of cells in the domesticated fruits. Plant biologists have recently discovered genes that are responsible for controlling cell division in tomatoes. Why would such a discovery be important to producers of other kinds of fruits and vegetables? To the study of human development and disease? To our basic understanding of biology?

The expression of the Pax-6 gene when vertebrate and fruit fly versions of the gene are exchanged between these animal groups illustrates __________.

In recombinant DNA technology, the term vector refers to __________.