MZdicer mutants
undergo axis formation and differentiate
multiple cell types but display abnormal morphogenesis during gastrulation, brain formation, somitogenesis, and heart
development.
For example, during T - cell
development genes encoding the TRB molecules are assembled from
multiple polymorphic gene segments that
undergo rearrangements and selection, generating Vb — Db — Jb combinations that are unique in both length and sequence.