However, the genes are more complex, with more alternative splicing generating a larger number of protein products. Hundreds of human genes appear likely to have resulted from horizontal transfer from bacteria at some point in the vertebrate lineage. Dozens of genes appear to have been derived from transposable elements. Although about half of the human genome derives from transposable elements, there has been a marked decline in the overall activity of such elements in the hominid lineage. The pericentromeric and subtelomeric regions of chromosomes are filled with large recent segmental duplications of sequence from elsewhere in the genome.
Segmental duplication is much more frequent in humans than in yeast, fly or worm.
Analysis of the organization of Alu elements explains the longstanding mystery of their surprising genomic distribution, and suggests that there may be strong selection in favour of preferential retention of Alu elements in GC-rich regions and that these 'selfish' elements may benefit their human hosts. The mutation rate is about twice as high in male as in female meiosis, showing that most mutation occurs in males. This collection should allow the initiation of genome-wide linkage disequilibrium mapping of the genes in the human population. In this paper, we start by presenting background information on the project and describing the generation, assembly and evaluation of the draft genome sequence. Finally, we discuss applications of the sequence to biology and medicine and describe next steps in the project.