PMCCPMCCPMCC

Conseils de recherche
Les critères de recherche 

Avancée

 
Logo of bmcgenoBioMed Centralsearchsubmit a manuscriptregisterthis articleBMC Genomics
 
BMC Genomics. 2009; 10: 177.
Published online Apr 24, 2009. doi:  10.1186/1471-2164-10-177
PMCID: PMC2694835
Phylogenetic reconstruction and the identification of ancient polymorphism in the Bovini tribe (Bovidae, Bovinae)
Sean MacEachern,corresponding author1,2,5 John McEwan,3 and Mike Goddard1,4
1Primary Industries Research Victoria, Animal Genetics and Genomics, Attwood VIC 3049, Australia
2Latrobe University, Department of Genetics, Bundoora VIC 3086, Australia
3Animal Genomics, AgResearch, Private Bag 50034, Mosgiel, New Zealand
4Melbourne University, School of Agriculture and Food Systems, Melbourne VIC 3000, Australia
5Avian Disease and Oncology Laboratory 3606 E Mt Hope Rd, East Lansing, Mi. 48823, USA
corresponding authorCorresponding author.
Sean MacEachern: sean.maceach/at/gmail.com; John McEwan: john.mcewan/at/agresearch.co.nz; Mike Goddard: mike.goddard/at/dpi.vic.gov.au
Received January 29, 2008; Accepted April 24, 2009.
Abstract
Background
The Bovinae subfamily incorporates an array of antelope, buffalo and cattle species. All of the members of this subfamily have diverged recently. Not surprisingly, a number of phylogenetic studies from molecular and morphological data have resulted in ambiguous trees and relationships amongst species, especially for Yak and Bison species. A partial phylogenetic reconstruction of 13 extant members of the Bovini tribe (Bovidae, Bovinae) from 15 complete or partially sequenced autosomal genes is presented.
Results
We identified 3 distinct lineages after the Bovini split from the Boselaphini and Tragelaphini tribes, which has lead to the (1) Buffalo clade (Bubalus and Syncerus species) and a more recent divergence leading to the (2) Banteng, Gaur and Mithan and (3) Domestic cattle clades. A fourth lineage may also exist that leads to Bison and Yak. However, there was some ambiguity as to whether this was a divergence from the Banteng/Gaur/Mithan or the Domestic cattle clade. From an analysis of approximately 30,000 sites that were amplified in all species 133 sites were identified with ambiguous inheritance, in that all trees implied more than one mutation at the same site. Closer examination of these sites has identified that they are the result of ancient polymorphisms that have subsequently undergone lineage sorting in the Bovini tribe, of which 53 have remained polymorphic since Bos and Bison species last shared a common ancestor with Bubalus between 5–8 million years ago (MYA).
Conclusion
Uncertainty arises in our phylogenetic reconstructions because many species in the Bovini diverged over a short period of time. It appears that a number of sites with ambiguous inheritance have been maintained in subsequent populations by chance (lineage sorting) and that they have contributed to an association between Yak and Domestic cattle and an unreliable phylogenetic reconstruction for the Bison/Yak clade. Interestingly, a number of these aberrant sites are in coding sections of the genome and their identification may have important implications for studying the neutral rate of mutation at nonsynonymous sites. The presence of these sites could help account for the apparent contradiction between levels of polymorphism and effective population size in domesticated cattle.
Les articles de BMC Genomics ont été offerts à titre gracieux par
BioMed Central.