Relationship between intron conservation and the numbers of exons. Linear regression analysis is performed to see the relationship between the degree of conservation in introns from each ordinal position and the numbers of exons within genes. Genes are grouped by the numbers of exons within genes. For example, as shown in the top left box in the figure, genes with two exons are grouped together (named G1), the average degrees of conservations in first introns of the genes in G1 in X-axis is shown on the Y-axis. As for G1, the conservations in first introns in genes with three exons (named G2) and up to genes with twenty-one exons (named G20) are calculated. Likewise, in the box for 2nd introns (shown in blue), genes are grouped as in the first box but now the conservation in second intron is estimated; likewise for introns 3 up to 10. Note that the numbers of dots decreases by one in each subsequent box, because Nth (N>=1) introns are non-existent in genes comprising less than N numbers of exons. Regression equations and R-squared values for each linear regression analysis are shown. The collection of plots suggests that there is strong correlation between first intron conservation and number of exons, specifically for the first intron, and much lesser extent for other introns.