The inherent occurrence of complex intron-rich spliceosomal split genes, including regulatory and splicing elements, within pre-biotic random genetic sequences
Growing evidence indicates that complex intron-rich split genes and an advanced spliceosome existed in the earliest eukaryote, and possibly the first life form. We sought to examine how these split genes could have originated in the prebiotic system. We previously found that split coding sequences for complex proteins occur in abundance in random DNA sequences (P. Senapathy, et al, accompanying paper). This study demonstrates that a full complement of exons, introns and regulatory and splicing elements could have also occurred inherently within pre-biotic chemistry by chance. By comparing the characteristics of split genes found in computer-generated random genetic sequences with those of several extant eukaryotes, we show that an abundance of intron-rich split genes akin to those present in modern eukaryotes could have existed in the prebiotic system. These findings answer the post-genomic question of why the earliest life form contained highly complex intron-rich split genes, and, in conjunction with our companion study, show how they could encode a complex spliceosome
