Figure 2. MB lineage analysis with twin-spot MARCM.

Examples of twin-spot MARCM clones used in an analysis of MB lineage are shown: two-cell + multi-cellular Nb clones (a-i) and two single-cell clones (j-u) in adult (a-r) and wandering larval (s-u) brains. Mitotic recombination was induced by FLP activity in MB Nbs (a-i) or GMCs (j-u) at different developmental stages, including 1^st instar larval (a-c, j-l and s-u), mid 3^rd instar larval (d-f and m-o) and mid-late pupal (g-i and p-r) stages. GAL4-OK107 (a-i and m-r) and MB247-GAL4 (j-l and s-u) were used to visualize twin-spot MARCM clones. In the two-cell + multi-cellular Nb clones: two γ MB neurons (a) are associated with a MB clone (b) highlighting all MB lobes (γ, α, α′, β and β′ lobes); two α′/β′ MB neurons (d) are associated with a MB clone (e) revealing α, α′, β and β′ lobes; two α/β MB neurons (g) are associated with a MB clone (h) containing only α and β lobes. In the two single-cell clones: a green γ MB neuron (j and s) is associated with the other magenta γ MB neuron (k and t); a green α′/β′ MB neuron (m) is associated with the other magenta α′/β′ MB neuron (n); a green α/β MB neurons (p) is associated with the other magenta α/β MB neuron (q). These analyses allow us to distinguish two-cell clones from double inductions in separate GMCs (j-u). The green and magenta merged images are shown in c, f, i, l, o, r and u.