The long-term debate of how bird wings evolved from five-digits to three-digits has been settled according to new evidence.
New evidence shows popular belief is correct and that bird wings stemmed from digits I, II and III, not from a digit frame shift.
Researchers were able to graft genetically modified embryonic tissue onto normal birds. The genetic modification created a fluorescent protein that helped analyze digit growth progress in a chick.
It is widely acknowledged the anatomy of bird wings is similar to the hands of Triassic theropod dinosaurs but cause of the debate was which digits stemmed the evolutional growth in bird wings.
Read more at Nature Communications