Comparison of genomic nucleotide sequences around the 92-bp exon of
various primate CMP-Neu5Ac hydroxylase genes. Hs, Pt, Gg, and Mm refer
to the human, chimpanzee, gorilla, and rhesus monkey, respectively. The
shaded boxes represent the 92-bp exon deleted in the hominid lineage.
The Alu element is represented by the open box. The
direct repeats of the sialic acid hydroxylase AluSq
(sahAluSq) are underlined. The arrowheads indicate
replacement boundaries. The 5′-TAAAGATTAATTTTTATTTTT-3′ sequence, which
would have a strong preference to the target-priming by the
Alu poly(A) tail, is located in the 5′ region
immediately adjacent to the upstream replacement boundary. Dots refer
to identical nucleotides in the other primates; dashes indicate gaps
used for sequence alignment. In the gap corresponding to the human
deletion, the complete sequences of the other primate genes are
shown.