Dear colleagues, Two papers on the evolution of killer whale types and forms have just been published online:
Mitogenomic insights into a recently described and rarely observed killer whale morphotype Andrew D. Foote, Phillip A. Morin, Robert L. Pitman, Maria C. Avila-Arcos, John W. Durban, Anton van Helden, Mikkel-Holger S. Sinding and M. Thomas P. Gilbert Polar Biology, DOI 10.1007/s00300-013-1354-0 Identifying evolutionary divergent taxonomic units, e.g. species and subspecies, is important for con- servation and evolutionary biology. The ‘type D’ killer whale, Orcinus orca, is a rarely observed morphotype with a pelagic, circumpolar subantarctic distribution, making dedicated research and therefore taxonomic study extremely difficult to date. In this study, we used DNA target enrichment hybridisation capture coupled to high throughput sequencing, to obtain the first DNA sequence from the only known museum specimen of this recently described morphotype. The high coverage, complete mitogenome sequence was compared to a previously published global dataset of 139 individuals, indicating that this type is highly divergent to all previously genetically sequenced killer whale forms. The estimated divergence time (390,000 years ago) from its most recent common ancestor with other extant killer whale lineages was the second oldest split within the killer whale phylogeny. This study provides the first genetic support of type D potentially being a distinct subspecies or species of killer whale, although further samples are needed to identify whether there is monophyly of mitogenome sequences and whether nuclear DNA also indicates reproductive isolation. These findings also highlight the value of natural history museum collections and new technologies to investigate the taxonomy of rare, cryptic or difficult to access species. http://link.springer.com/article/10.1007/s00300-013-1354-0#page-1 Tracking niche variation over millennial timescales in sympatric killer whale lineages Andrew D. Foote, Jason Newton, Maria C. Avila-Arcos, Marie-Louise Kampmann, Jose A. Samaniego, Klaas Post, Aqqalu Rosing-Asvid, Mikkel-Holger S. Sinding and M. Thomas P. Gilbert Proceedings of the Royal Society B, 280: 20131481 Niche variation owing to individual differences in ecology has been hypothesized to be an early stage of sympatric speciation. Yet to date, no study has tracked niche width over more than a few generations. In this study, we show the presence of isotopic niche variation over millennial timescales and investigate the evolutionary outcomes. Isotopic ratios were measured from tissue samples of sympatric killer whale *Orcinus orca*lineages from the North Sea, spanning over 10,000 years. Isotopic ratios spanned a range similar to the difference in isotopic values of two known prey items, herring *Clupea harengus* and harbour seal *Phoca vitulina*. Two proxies of the stage of speciation, lineage sorting of mitogenomes and genotypic clustering, were both weak to intermediate indicating that speciation has made little progress. Thus, our study confirms that even with the necessary ecological conditions, i.e. among-individual variation in ecology, it is difficult for sympatric speciation to progress in the face of gene flow. In contrast to some theoretical models, our empirical results suggest that sympatric speciation driven by among-individual differences in ecological niche is a slow process and may not reach completion. We argue that sympatric speciation is constrained in this system owing to the plastic nature of the behavioural traits under selection when hunting either mammals or fish. http://rspb.royalsocietypublishing.org/content/280/1768/20131481.abstract best regards, Andy Foote and coauthors -- *Dr Andrew Foote* *Centre for GeoGenetics* The Natural History Museum of Denmark Øster Voldgade 5 - 7 1350 Copenhagen K
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