It seems to be saying that the genetics for wings, many of the physical constructs of wings, and the neurology for wings, are retained over long periods.
"Entomologists have long assumed that re-evolution of wings in apterous lineages was impossible, because functional wings require complex interactions among multiple structures, and the associated genes would be free to accumulate mutations in wingless lineages, effectively blocking the path for any future wing reacquisition. However, this assumption requires that developmental pathways for wing formation are largely independent of pathways required for development of other structures. For instance, in Drosophila and other insects, leg and wing imaginal discs have a common origin from a single group of cells and the developmental pathway for wing determination has been largely co-opted (recruited) from the pathway required for limb formation15, 16. Therefore it is not surprising that the basic genetic instructions for wing formation are conserved in wingless insects, because similar instructions are required to form legs, and probably other critical structures16. Studies of flight motor patterns in flying and non-flying phasmids indicate that the non-flying phasmids have retained the neural structures and basic functional circuitry required for flight, as indicated by flight-specific neural activity in thoracic muscles17, demonstrating that the loss of wings does not correlate with the loss of flight musculature and innervation. Wing development depends on multiple gene systems, transcription factors, secreted proteins, and receptors15, and mutations in any one of these factors may lead to winglessness. Given the multitude of factors involved in wing formation, it seems probable that the specific cause for winglessness will differ from lineage to lineage, but that the basic blueprint for wing formation can remain largely intact, even over large evolutionary time periods."
This would seem to say that the reintroduction of wings is really due to a "switch" and not due to the re-evolution of all of the structures and physiology of wings. If that is the case, it doesn't hold much of a surprise.
Did you know that elephants are loosing their tusks to help them survive dealing with poachers? It will be interesting to see where this goes. If they lose them now, can they gain them back later?
http://news.bbc.co.uk/1/hi/world/africa/180301.stm
Let's just hope that the chickens never get their teeth back! That would be to scary.
http://www.talkorigins.org/faqs/comdesc/section2.html#ontogeny_ex6
" During development in reptiles (and mammals), dental enamel forms from epithelial tissue which lines the surface of the gum, while the dentin which makes teeth is produced from a deeper tissue called the mesenchyme. However, in birds, this epithelial layer normally develops instead into the keratinous beak. Kollar and Fisher transplanted a small piece of mammalian mesenchymal tissue (which forms teeth) underneath the beak-forming epithelial layer of a developing chick (Kollar and Fisher 1980). Intriguingly, they observed that the chicken epithelium secreted dental enamel and directed the adjacent mesenchyme to form teeth. This would have been impossible unless the chicken still retained the genes and developmental pathway for making teeth. Thus, chickens have not yet completely lost the genes coding for tooth development."
