Chicken grows teeth

The actual Talpid² mutant is unlikely to be in any unexpressed 'reptile' gene. The Talpid mutantis though to be important in Sonic hedgehog signalling which is one of the major developmental signalling pathways which affects a large number of developing structures.It is certainly interesting that the chick mesenchyme still shows the ability to develop teeth transiently in the Talpid² mutant, but it doesn't neccessarily ned any cryptic normally unexpressed 'reptile' gene, it does however suggest that there have been some conserved elements which have persisted which might have been expected to have been lost due to lack of use.TTFN,WK