Comparison of intron-containing and intron-lacking human genes elucidates putative exonic splicing enhancers

Of the rules used by the splicing machinery to precisely determine intron-exon boundaries only a fraction is known. Recent evidence suggests that specific short sequences within exons help, in defining these boundaries. Such sequences known as exonic splicing enhancers (ESE), A possible bioinformatical approach to studying ESE sequences is to compare genes that harbor introns with genes that do not, For this purpose two nonredundant samples of 719 intron-containing and 63 intron-lacking human genes were created. We performed a statistical analysis on these datasets of intron-containing and intron-lacking human coding sequences and found a statistically significant difference (P = 0.01) between these samples in terms of 5-6mer oligonucleotide distributions. The difference is not created by a few strong signals present in the majority of exons, but rather by the accumulation of multiple week signals through small variations in codon frequencies, codon biases and context-dependent codon biases between the samples, A list of putative novel human splicing regulation sequences has been elucidated by our analysis.