Nucleotide sequence analysis of human beta-globin gene by the quantification method: mutations in 3'-splice junction sequence and beta-thalassemia.

The nucleotide sequence at the intron-exon junction in the human beta-globin gene was analyzed by the quantification method (categorical discriminant analysis) proposed previously. Using the sample score of a 16-nucleotide sequence at a 3'-splice junction, we studied to what extent such a sequence contains the 3'-splice signal. To examine the applicability of our method, we further studied several mutants of beta-thalassemia, where nucleotide changes exist at 3'-splice junction sequences of the first and second introns. Other mutants involve point mutations which generate new 3'-splice signals within the first intron. Experimental results on the abnormal splicing in those mutants could be explained in terms of the sample scores of 16-nucleotide sequences and their locations relative to the branch point.