A genome is the complete collection of an organism's genetic material. The human genome is composed of about 50,000 to 100,000 genes located on the 23 pairs of chromosomes in a human cell. A single human chromosome may contain more than 250 million DNA base pairs, and it is estimated that the entire human genome consists of about 3 billion base pairs.
The DNA being analyzed in the Human Genome Project typically comes from small samples of blood or tissue obtained from many different people. Although the genes in each person's genome are made up of unique DNA sequences, the average variation in the genomes of two different people is estimated to be much less than 1 percent. Thus the differences between human DNA samples from various sources are small in comparison to their similarities.
In general, genetic enhancement refers to the transfer of genetic material intended to modify non-pathological human traits.
The term commonly is used to describe efforts to make someone not just well, but better than well, by optimizing attributes or capabilities - perhaps by raising an individual from standard to peak levels of performance. Gene insertion may be intended to affect a single individual through somatic cell modification, or it may target the gametes, in which case the resulting effect could be passed on to succeeding generations.
The concept of genetic enhancement is not particularly recent if one considers genetically engineered drug products used to alter physical traits as genetic enhancements. For example, human growth hormone (HGH), which before 1985 could be obtained only in limited quantities from cadaveric pituitary glands, now can be produced using recombinant DNA technology. When its supply was more limited, HGH was prescribed for children with short stature caused by classical growth hormone deficiency. However, with the advent of recombinant DNA...