Comparative chromosome painting in Columbidae (Columbiformes) reinforces divergence in Passerea and Columbea

Pigeons and doves (Columbiformes) are one of the oldest and most diverse extant lineages of birds. However, the karyotype evolution within Columbiformes remains unclear. To delineate the synteny-conserved segments and karyotypic differences among four Columbidae species, we used chromosome painting from Gallus gallus (GGA, 2n=78) and Leucopternis albicollis (LAL, 2n=68). Besides that, a set of painting probes for the eared dove, Zenaida auriculata (ZAU, 2n=76), was generated from flow-sorted chromosomes. Chromosome painting with GGA and ZAU probes showed conservation of the first ten ancestral pairs in Z. auriculata, Columba livia, and Columbina picui, while in Leptotila verreauxi, fusion of the ancestral chromosomes 6 and 7 was observed. However, LAL probes revealed a complex reorganization of ancestral chromosome 1, involving paracentric and pericentric inversions. Because of the presence of similar intrachromosomal rearrangements in the chromosomes corresponding to GGA1q in the Columbidae and Passeriformes species but without a common origin, these results are consistent with the recent proposal of divergence within Neoaves (Passerea and Columbea). In addition, inversions in chromosome 2 were identified in C. picui and L. verreauxi. Thus, in four species of distinct genera of the Columbidae family, unique chromosomal rearrangements have occurred during karyotype evolution, confirming that despite conservation of the ancestral syntenic groups, these chromosomes have been modified by the occurrence of intrachromosomal rearrangements.