Changes in Hox genes' structure and function during the evolution of the squamate body plan.
Hox genes are central to the specification of structures along the anterior-posterior body axis, and modifications in their expression have paralleled the emergence of diversity in vertebrate body plans. Here we describe the genomic organization of Hox clusters in different reptiles and show that squamates have accumulated unusually large numbers of transposable elements at these loci, reflecting extensive genomic rearrangements of coding and non-coding regulatory regions. Comparative expression analyses between two species showing different axial skeletons, the corn snake and the whiptail lizard, revealed major alterations in Hox13 and Hox10 expression features during snake somitogenesis, in line with the expansion of both caudal and thoracic regions. Variations in both protein sequences and regulatory modalities of posterior Hox genes suggest how this genetic system has dealt with its intrinsic collinear constraint to accompany the substantial morphological radiation observed in this group.
Di-Poï
Nicolas
N
National Research Center Frontiers in Genetics, Department of Zoology and Animal Biology, University of Geneva, Sciences III, 1211 Geneva 4, Switzerland.
Montoya-Burgos
Juan I
JI
Miller
Hilary
H
Pourquié
Olivier
O
Milinkovitch
Michel C
MC
Duboule
Denis
D
D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D019521:Body Patterning / Q000235:genetics*; D017812:Colubridae / Q000196:embryology / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox / Q000235:genetics*; D016678:Genome / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism*; D008116:Lizards / Q000196:embryology / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D019170:Somites / Q000196:embryology / Q000378:metabolism
D004251:DNA Transposable Elements; D018398:Homeodomain Proteins