[Pericentric inversion of no. 3, homozygous and heterozygous, and centromeric transposition of no. 12 in a family of orangutans. Implications for evolution].

An orang-utan family is reported in which the father (Piku) is homozygous for a pericentric inversion of chromosome 3 and heterozygous for a structural rearrangement of chromosome 12 (author's nomenclature for this species). The latter is interpreted as transposition of the centromere by insertion into band q213 [ins cen(12)(q213)]. Piku's mate has a normal female chromosome complement. His daughters by this mate (Agnès and Ursula) are heterozygous for both his rearrangements. A fifth orang-utan (Arnold) captured on a different Malesian island was found to have one chromosome 12 similar to that of Piku, and to have a female complement, even though his keapers considered him male. Several hypotheses are proposed to explain the observations, including consanguinity, the existence of a common polymorphism in the species, and the existence of an established subspecies among orang-utans.