Sequence Simplicity and Evolution of the 3'
Untranslated Region of the Histone H1o Gene
Imma Ponte, Claudio Monsalves, Miguel Cabañas, Pedro
Martínez, Pedro Suau
Journal of Molecular Evolution
43:125-134 (1996)
Abstract
The H1o gene has a long 3' untranslated region
(3'UTR) of 1,125 nucleotides in the rat and 1,310 in
humans. Analysis of the sequences shows that they
have features of simple DNA that suggest involvement
of replication slippage in their evolution. These
features include the length imbalance between the rat
and human sequences; the abundance of single-base
repeats, two-base runs and other simple motifs
clustered along the sequence; and the presence of
single-base repeat length polymorphisms in the rat
and mouse sequences. Pairwise comparisons show
numerous short insertions/deletions, often flanked by
direct repeats. In addition, a proportion of short
insertions/deletions results from length differences
in conserved single-base repeats. Quantification of
the sequence simplicity shows that simple sequences
have been more actively incorporated in the human
lineage than in the rodent lineage. The combination
of insertions/deletions and nucleotide substitutions
along the sequence gives rise to three main regions
of homology: a highly variable central region flanked
by more conserved regions nearest the coding region
and the polyA addition site.
