A complete mitochondrial genome sequence of the wild two-humped camel Camelus bactrianus ferus: an evolutionary history of camelidaeReportar como inadecuado




A complete mitochondrial genome sequence of the wild two-humped camel Camelus bactrianus ferus: an evolutionary history of camelidae - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

BMC Genomics

, 8:241

First Online: 18 July 2007Received: 17 March 2007Accepted: 18 July 2007

Abstract

BackgroundThe family Camelidae that evolved in North America during the Eocene survived with two distinct tribes, Camelini and Lamini. To investigate the evolutionary relationship between them and to further understand the evolutionary history of this family, we determined the complete mitochondrial genome sequence of the wild two-humped camel Camelus bactrianus ferus, the only wild survivor of the Old World camel.

ResultsThe mitochondrial genome sequence 16,680 bp from C. bactrianus ferus contains 13 protein-coding, two rRNA, and 22 tRNA genes as well as a typical control region; this basic structure is shared by all metazoan mitochondrial genomes. Its protein-coding region exhibits codon usage common to all mammals and possesses the three cryptic stop codons shared by all vertebrates. C. bactrianus ferus together with the rest of mammalian species do not share a triplet nucleotide insertion GCC that encodes a proline residue found only in the nd1 gene of the New World camelid Lama pacos. This lineage-specific insertion in the L. pacos mtDNA occurred after the split between the Old and New World camelids suggests that it may have functional implication since a proline insertion in a protein backbone usually alters protein conformation significantly, and nd1 gene has not been seen as polymorphic as the rest of ND family genes among camelids. Our phylogenetic study based on complete mitochondrial genomes excluding the control region suggested that the divergence of the two tribes may occur in the early Miocene; it is much earlier than what was deduced from the fossil record 11 million years. An evolutionary history reconstructed for the family Camelidae based on cytb sequences suggested that the split of bactrian camel and dromedary may have occurred in North America before the tribe Camelini migrated from North America to Asia.

ConclusionMolecular clock analysis of complete mitochondrial genomes from C. bactrianus ferus and L. pacos suggested that the two tribes diverged from their common ancestor about 25 million years ago, much earlier than what was predicted based on fossil records.

Abbreviationscox1, cox2, cox3cytochrome oxidase subunit I, II, and III protein genes

atp6, atp8ATP synthase subunit 6 and 8 geness

nad1, nad2, nad3, nad4, nad5, nad6, nad4LNADH dehydrogenase subunit 1–6, 4L genes

cytbcytochrome b gene

mtDNAmitochondrial DNA

AAamino acids.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2164-8-241 contains supplementary material, which is available to authorized users.

Peng Cui, Rimutu Ji contributed equally to this work.

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Autor: Peng Cui - Rimutu Ji - Feng Ding - Dan Qi - Hongwei Gao - He Meng - Jun Yu - Songnian Hu - Heping Zhang

Fuente: https://link.springer.com/article/10.1186/1471-2164-8-241







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