Sequence variation in the Tbx4 gene in marine mammals

Onbe, Kaori; Nishida, Shin; Sone, Emi; Kanda, Naohisa; Goto, Mutsuo; Pastene, Luis A.; Tanabe, Shinsuke; Koike, Hiroko


The amino-acid sequences of the T-domain region of the Tbx4 gene, which is required for hindlimb development, are 100% identical in humans and mice. Cetaceans have lost most of their hindlimb structure, although hindlimb buds are present in very early cetacean embryos. To examine whether the Tbx4 gene has the same function in cetaceans as in other mammals, we analyzed Tbx4 sequences from cetaceans, dugong, artiodactyls and marine carnivores. A total of 39 primers were designed using human and dog Tbx4 nucleotide sequences. Exons 3, 4, 5, 6, 7, and 8 of the Tbx4 genes from cetaceans, artiodactyls, and marine carnivores were sequenced. Non-synonymous substitution sites were detected in the T-domain regions from some cetacean species, but were not detected in those from artiodactyls, the dugong, or the carnivores. The C-terminal regions contained a number of non-synonymous substitutions. Although some indels were present, they were in groups of three nucleotides and therefore did not cause frame shifts. The d(N)/d(S) values for the T-domain and C-terminal regions of the cetacean and artiodactylous Tbx4 genes were much lower than 1, indicating that the Tbx4 gene maintains it function in cetaceans, although full expression leading to hindlimb development is suppressed.

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Título según WOS: ID WOS:000247300100004 Not found in local WOS DB
Título de la Revista: ZOOLOGICAL SCIENCE
Volumen: 24
Número: 5
Editorial: Sociedad Zoológica de Japón
Fecha de publicación: 2007
Página de inicio: 449
Página final: 464


Notas: ISI