Apolipoprotein C-I is present in acidic (APOC1A) and basic (APOC1B) forms in P.paniscus, P.abelii and P.troglodytes and perhaps also in baboons and macaques. The two genes for ApoC-I arose through a duplication process that occurred after the divergence of New World monkeys from the human lineage. In human, the acidic form has become a pseudogene sometime between the divergence of bonobos and chimpanzees from the human lineage and the appearance of the Denisovans. Pseudogenization resulted when the codon for the penultimate amino acid in the signal sequence was changed to a stop codon. Belongs to the apolipoprotein C1 family.