The samples are taken from the sperm of males and the blood of females. Sperm is being taken from males because it contains the Y chromosome that female cells lack. The donations of sperm and blood are strictly anonymous. Researchers are also studying the genomes of Drosophila and laboratory mice to aid in the project. Determining the three billion bases and approximately 100,000 genes of the human genome is being accomplished by sequencing.
Scientists begin sequencing by cutting DNA with restriction enzymes.
These enzymes cut the DNA at specific sites on the strand. The next step is to use gel electrophoresis to separate different sized fragments that may have been produced by different individuals when treated with the restriction enzyme. The gel allows different sized particles to move at different rates when an electric field is produced. The smaller fragments move more quickly down the gel than the larger particles. After a clone library is achieved, sequencing can begin.