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Message: <blockquote data-quote="l_raty" data-source="post: 2868872" data-attributes="member: 24811">Hi Brian,Of course, the mitochondrial control region is not coding for the plumage/structure differences that you see in the field. Hence, if there are differences, and if they have a genetic basis (rather than being just plasticity in response to local conditions, such as available food, etc.), they must lie hidden somewhere else in the genome.If two (meta)populations are isolated (ie, no gene flow between them, be it for intrinsic reasons or due to geography), their genome is expected to diverge.Now, if these (meta)populations are morphologically differentiated, yet there is no divergence in a gene, this can mean either- that gene flow is occurring (but doesn't stop the morphologiocal differentiation--this would be expected, eg, if the differences are maintained by different selective forces acting in the ranges of the two forms), or- that gene flow is not occurring anymore but was still relatively recently (iow, the separation is recent), and that the morphological differences evolved faster than differences in the gene you are looking at.For slowly evolving nuclear genes, it is not infrequent that no difference can be seen even between well differentiated taxa. The mitochondrial genome, on the other hand, evolves rather fast, making this type of situation much less common. Yet sister taxa that are almost universally treated as species can appear undifferentiated as well (eg. Ortolan vs. Cretzschmar's Bunting, Yellowhammer vs. Pine Bunting, Parrot vs. (nominate) Common Crossbill, Arctic vs. Common Redpoll, or even Pallid vs. Common Swift--and I'm not even talking of large gulls, large skuas, or ducks from the mallard group).That said, as I wrote above, I don't know at all how Mundy & Helbig identified their birds, and it is probably conceivable that the niloticus was ID'd on range only (Israel). Intriguingly, <a href="http://www.boldsystems.org/" target="_blank">BOLD</a> (a growing database of sequences of the mitochondrial "cytochrome c oxidase subunit 1" gene, aka "DNA barcodes") has sequences from 3 Woodchat Shrikes from Israel, 3 from Greece, and 2 from Iraq: the Israeli birds there appear very similar to the Greek birds, while the Iraqi birds are somewhat divergent (see <a href="http://www.boldsystems.org/index.php/Public_BarcodeCluster?clusteruri=BOLD:AAF4304" target="_blank">here</a>). Pictures of the Isreali and Iraqi birds can be accessed from <a href="http://www.boldsystems.org/index.php/Public_SearchTerms?query=BOLD:AAF4304" target="_blank">here</a>. Any insight about the subspecies of the Israeli birds?Cheers, Laurent -</blockquote>

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