Table S1. Detailed Information About the Clones Used for In Situ Hybridization

Gene Name GenBank ID Left primer Right primer Amplicon size Btg1 NM_007569 TGCCATAGTTTGGACAGTACC CAAAATAGATGGTGGTTTGTGG 635 Cav1 NM_007616 ACCTCTCTGGACTGGCAGAA AGTGTCGGCAAGACTGAAGG 653 Chn2 NM_023543 GCATGAGATTTCCACACCAA TTTCCTTCCATTACACTGTCATAA 407 Cited2 NM_010828 TGCTGCCACTTTTTCCTATTC TCTGTGAAATGTTTGCCACTG 501 Cpne4 NM_028719 TGACACAAATTCCTGGACAATC CAGTGAGCTCAAAGACCAAGC 551 Cux2 NM_007804 TCAGTCAACAGCTCCATTCG GACAGCGAGAAAGTCCTTGG 626 Dkk3 NM_015814 ATTGGGTTCACCATTTCAGG CAGGCGTTTAAGAGGTACTCG 617 Epha3 NM_010140 GTCCAAATGCCTTAAAATGG CAATAGCATTTGGCACTTGG 595 Frmd4b NM_145148 AGCTCCTGAATCGTGGCTTA TCCTGCAGCTCGGAGTAAAT 603 Gfra2 NM_008115 GATGTGAACATGTCTCCCAAAG ATTTTGTCAGGCGGGAGTTC 382 Gm879 NM_001034874 AATGGGTTTGGCATTGTAGC AATTTCCATTGGTGCTTTGC 523 Gpr88 NM_022427 CAAATGAAACCAATGGTCAGG TATCTGTTTCCCGTGTCTCC 514 Hspb3 NM_019960 TGATTCAGCCCCAATTAAGC CTGGGGTATGAAGAGCAACC 632 Inhba NM_008380 GCGATCAGAAAGCTTCATGTG AGACTGGCACCACTCTCCTG 506 Limch1 NM_001001980 AGCCAGACACGAAAGGAATG GCAAACACCTCCGAGAGAAG 509 Lpl NM_008509 TGCTGTGCAAAGAGAAGAGC CGGACACAAAGTTAGCACCA 658 Nectin-3 NM_021495 AAACAACCTGATCCGCAAAG CAGTGAAAACTGTAAAGCAGCTC 466 Nnmt NM_010924 CCTATGTGTGTGATCTTGAAGG AGATCTGCCTGGCTTTCG 455 PlxnD1 NM_026376 CAGGAAATGAACGCACACC TGAGGGACACAGACAACTGC 656 Ptn NM_008973 GCCTACCCGTCCAAATATCC GCCAGTTCTGGTCTTCAAGG 590 TcrB X67128 GGGTTCTGTCTGCAACCATC AAGGTGTCAACGAGGAAGGA 244 Tmtc4 NM_028651 GAAGCAGAGCAGAGCTACCG TCTGAACAGAGGCTTCATGC 579

Table S2: Selected subset of the identified by microarray analysis that are expressed at

higher levels in callosal projection neurons compared to corticospinal motor neurons and

corticotectal projection neurons. The forty genes listed are those with the most biologically

significant and distinctive expression profiles following temporal analysis of expression

data. Genes that were further investigated with in situ hybridization are listed in bold.

Gene Name Full Name GenBank ID Adamts3 ADAM metallopeptidase with thrombospondin type 1 motif, 3 NM_001081401 Btg1 B-cell translocation gene 1 NM_007569 C030017B01Rik EST (located 3' of Kctd16) AK046738 Cav1 Caveolin (caveolae 1) NM_007616 Cdh10 Cadherin 10 NM_009865 Chn2 2 NM_023543 Cited2 Cbp/p300-interacting transactivator, with Glu/Asp-rich carboxy-terminal domain, 2 NM_010828 Coup-tfI Chicken ovalbumin upstream promoter-transcription-factor 1 NM_010151 Cpne4 Copine 4 NM_028719 Cux1 Cut-like 1 NM_009986 Cux2 Cut-like 2 NM_007804 DCC Deleted in colorectal carcinoma NM_007831 Dkk3 Dickkopf homolog 3 NM_015814 Epha3 Eph receptor A3 NM_010140 Frmd4b FERM domain containing 4B NM_145148 Gfra2 Glial cell line derived neurotrophic factor family receptor alpha 2 NM_008115 Gm879 Gene model 879 NM_001034874 Gpr6 G-protein-coupled receptor 6 NM_199058 Gpr88 G-protein coupled receptor 88 NM_022427 Gria4 Glutamate receptor, ionotropic, AMPA4 BB130399 Grp Gastrin releasing peptide NM_175012 Hspb3 Heat shock protein 3 NM_019960 Inhba Inhibin beta-A NM_008380 Kcnh1 Potassium voltage-gated channel, subfamily H, member 1 NM_001038607 Klhl4 Kelch-like 4 NM_172781 Lhx2 LIM homeobox protein 2 NM_010710 Limch1 LIM and calponin homology domains 1 NM_001001980 Lpl Lipoprotein lipase; NM_008509 Nectin-3 Nectin-3 NM_021495 Nnmt Nicotinamide N-methyltransferase NM_010924 Pdzrn3 PDZ domain containing RING finger 3 NM_018884 Plxdc2 plexin domain containing 2 NM_026162 PlxnD1 Plexin-D1 NM_026376 Ptn NM_008973 Ptprk Protein tyrosine phosphatase, receptor type, K NM_008983 Satb2 Special AT-rich sequence binding protein 2 NM_139146

2 TcrB T-cell receptor beta X67128 Tmtc4 (J22rik) transmembrane and tetratricopeptide repeat containing 4 NM_028651 Unc5d Unc-5 homolog D NM_153135 Vglut2 Vesicular glutamate transporter 2 NM_080853

3