For GSS Losing Biodiversity chapter 4. Excerpt: ...Using the labor of dozens of undergraduate students, scientists have built a customized yeast chromosome from scratch. It's a milestone in the rapidly growing field of synthetic biology, where organisms can be tailored for industrial use. In this case, the near-term goal is to understand the genetics of yeast, and eventually the genetics of us. This was quite an undertaking. Yeast have about 6,000 genes packed in 16 tidy bundles called chromosomes. Each chromosome is an enormous molecule of DNA packed in proteins. ...[Jef] Boeke and his colleagues put together a class, called Build-A-Genome, and got undergraduates at Hopkins to do the painstaking labor of constructing long strings of DNA. These would eventually become segments of their yeast chromosome. ...To make the chromosome useful for research, they've deleted some parts of the DNA that they believe are not essential, "and then we add a number of bells and whistles to the chromosome, that we think will make for a more interesting version that we can play evolutionary games with in the laboratory," Boeke says. ...Of course, this deep manipulation of DNA also raises ethical questions — about everything from patenting life-forms, to the potential misuse of biotechnology for weapons or other nefarious purposes. So part of the class involved an ethics discussion, led by Debra Mathews, a bioethicist at Johns Hopkins.... http://www.npr.org/blogs/health/2014/03/27/295260600/custom-chromo-first-yeast-chromosome-built-from-scratch. Richard Harris, NPR.