The mitochondrial DNA molecule of sumatran orangutan and a molecular proposal for two (Bornean and Sumatran) species of orangutan

Abstract

The complete mitochondrial DNA (mtDNA) molecule of Sumatran orangutan, plus the complete mitochondrial control region of another Sumatran specimen and the control regions and five protein-coding genes of two specimens of Bornean orangutan were sequenced and compared with a previously reported complete mtDNA of Bornean orangutan. The two orangutans are presently separated at the subspecies level. Comparison with five different species pairs-namely, harbor seal/grey seal, horse/donkey, fin whale/blue whale, common chimpanzee/pygmy chimpanzee, and Homo/common chimpanzee-showed that the molecular difference between Sumatran and Bornean orangutan is much greater than that between the seals, and greater than that between the two chimpanzees, but similar to that between the horse and the donkey and the fin and blue whales. Considering their limited morphological distinction the comparison revealed unexpectedly great molecular difference between the two orangutans. The nucleotide difference between the orangutans is about 75% of that between Homo and the common chimpanzee, whereas the amino acid difference exceeds that between Homo and the common chimpanzee. On the basis of their molecular distinction we propose that the two orangutans should be recognized as different species, Pongo pygmaeus, Bornean orangutan, and P. abelii, Sumatran orangutan.

Genetic Divergence of Orangutan Subspecies (Pongo pygmaeus)

“…In addition to ND5 data, orangutan DNA sequences from other mitochondrial regions have been previously reported (Ruvolo et al 1994;Xu and Arnason 1996a;Zhi et al 1996;Muir et al 2000). Here we also reanalyzed 16s rRNA data from Zhi et al (1996) (see Table 1).…”

“…Recently, studies of chromosomes, proteins, DNA hybridization, mtDNARFLPs, mtDNA sequences, minisatellites, etc., have demonstrated that the genetic differences between the two orangutans are almost the same as or even higher than those of other putative species like chimpanzee/ bonobo, horse/donkey, etc. (Bruce and Ayala 1979;Ferris et al 1981;Caccone and Powell 1989;Janczewski et al 1990;Ryder and Chemnick 1993;Xu and Arnason 1996a;Zhi et al 1996;Muir et al 2000). Based on these differences, some researchers have suggested that the two orangutans should be elevated to be separate species (Xu and Arnason 1996a).…”

“…The two subspecies differ cytogenetically by a pericentric inversion of chromosome 2, and this difference has been used as an index of subspecies for captivity management (Seuanez et al 1979;Ryder and Chemnick 1993). However, molecular genetic data from protein electrophoresis (Bruce and Ayala 1979), DNA hybridization (Caccone and Powell 1989), isozyme, two-dimensional electrophoresis (Janczewski et al 1990), mtDNA-RFLP, mtDNA sequences, and minisatellites (Ferris et al 1981;Ryder and Chemnick 1993;Xu and Arnason 1996a;Zhi et al 1996;Muir et al 2000) have demonstrated that the differences between the two subspecies are almost the same as or even higher than those between recognized species, e.g., chimpanzee (Pan troglodytes) vs. bonobo (Pan paniscus), horse (Equus caballus) vs. donkey (Equus asinus), etc. Some authors suggest the two orangutan subspecies should be elevated to species status (Xu and…”

Dental tissue proportions in fossil orangutans from mainland Asia and Indonesia

“…[17][18][19][20][21] de Vos 22,23 has argued that the Indonesian paleoenvironmental record reveals a more recent divergence, while Harrison et al 15 hypothesized that orangutans dispersed into Sundaland during a cold phase in the late Pliocene (~2.7 mya) and fragmented at the start of the Pleistocene (~1.8 mya), becoming genetically distinct subsequent to this. Unfortunately little is known about the biogeography of Early Pleistocene orangutans, due in part to the limited fossil record, lack of securely dated sites, and ambiguity regarding the taxonomic identification of primate material.…”

The Hunting of the SNaRC: A Snarky Solution to the Species Problem

“…Over the last twenty years there have been debates over the specific status of Sumatran (Pongo abelii) and Bornean orangutans (Pongo pygmaeus) (Groves 1986;Hobolth, Dutheil, et al 2011;Xu and Arnason 1996), based primarily on genomic data (Locke, Hillier, et al 2011). For most of the twentieth century, primatologists identified one orangutan species (P. pygmaeus) and several subspecies.…”