EVOLUTIONARY RATES OF INSERTION AND DELETION IN NONCODING NUCLEOTIDE-SEQUENCES OF PRIMATES

Insertions and deletions are responsible for gaps in aligned nucleotid e sequences, but they have been usually ignored when the number of nuc leotide substitutions was estimated. We compared six sets of nuclear a nd mitochondrial noncoding DNA sequences of primates and obtained the estimates of the evolutionary rate of insertion and deletion. The maxi mum-parsimony principle was applied to locate insertions and deletions on a given phylogenetic tree. Deletions were about twice as frequent as insertions for nuclear DNA, and single-nucleotide insertions and de letions were the most frequent in all events. The rate of insertion an d deletion was found to be rather constant among branches of the phylo genetic tree, and the rate (similar to 2.0/kb/Myr) for mitochondrial D NA was found to be much higher than that (similar to 0.2/kb/Myr) for n uclear DNA. The rates of nucleotide substitution were about 10 times h igher than the rate of insertion and deletion for both nuclear and mit ochondrial DNA.