A few years ago biologists found that a prominent change in pigeon plumage, head crests, could be traced to a mutation in a single gene. Now the research team has found an almost exact repeat in the evolutionary playbook in distantly related doves.
Evolutionary playbook? Doesn’t that imply a strategy? Oh wait, that’s heresy. Watch your language around Top People!
Evolutionary biologist Michael Shapiro and his team from the University of Utah made international headlines in 2013 when they found that a prominent change in pigeon plumage, head crests, could be traced to a mutation in a single gene.
Now, in the new advanced online edition of Molecular Biology and Evolution, the research team has found an almost exact repeat in the evolutionary playbook. A mutation in the same gene, EphB2, has led to a similar result in domesticated ringneck doves. The mutation causes the feathers on the back of the head and neck to grow up toward the head in a striking look.
“We know that many genes are involved in feather development, so it’s rather remarkable that the same gene appears to control the same trait in two distantly related species,” said Shapiro.
Next, armed with new DNA banks of bird species, Shapiro’s team will examine how far and wide this unique evolutionary twist may be found amongst other bird species and wild populations.
Here’s the abstract:
Head crests are important display structures in wild bird species and are also common in domesticated lineages. Many breeds of domestic rock pigeon (Columba livia) have crests of reversed occipital feathers, and this recessive trait is associated with a non-synonymous coding mutation in the intracellular kinase domain of EphB2. The domestic ringneck dove (Streptopelia risoria) also has a recessive crested morph with reversed occipital feathers, and interspecific crosses between crested doves and pigeons produce crested offspring, suggesting a similar genetic basis for this trait in both species. We therefore investigated EphB2 as a candidate for the head crest phenotype of ringneck doves and identified a non-synonymous coding mutation in the intracellular kinase domain that is significantly associated with the crested morph. This mutation is over 100 amino acid positions away from the crest mutation found in rock pigeons, yet both mutations are predicted to negatively affect function of the ATP-binding pocket. Furthermore, bacterial toxicity assays suggest that crest mutations in both species severely impact kinase activity. We conclude that head crests are associated with different mutations in the same functional domain of the same gene in two different columbid species, thereby representing striking evolutionary convergence in morphology and molecules. (paywall) – Convergent evolution of head crests in two domesticated columbids is associated with different missense mutations in EphB2. Anna I. Vickrey, Eric T. Domyan, Martin P. Horvath, and Michael D. Shapiro. Mol Biol Evol, June 23, 2015 DOI: 10.1093/molbev/msv140
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