Fig. 4. Combined deletions in cis. (A) Scheme of the posterior Hoxd complex, with the location of conserved regions X to XII. (B) The first combined deletion in cis was produced by meiotic recombination between the Hoxd^RXII and Hoxd^RXI alleles. Recombination (broken line) between the two loxP sites present in these alleles generated the Hoxd^RXII-del(13) allele (boxed), which carries a deletion of RXII as well as of the Hoxd13 locus containing RXI. (C) The second combined deletion in cis was produced by meiotic recombination between the Hoxd^RXII and Hoxd^RX alleles. Recombination (broken line) between the loxP sites present in these alleles generated the Hoxd^{RXII-del(13-12)} allele (boxed), which carries a deletion of RXII, as well as of both Hoxd13 and Hoxd12 loci, which contain both RXI and RX.