News archives


OCTOBER - DECEMBER 17

JULY - SEPTEMBER 17

APRIL - JUNE 17

JANUARY - MARCH 17

OCTOBER - DECEMBER 16

JULY - SEPTEMBER 16

APRIL - JUNE 16

JANUARY - MARCH 16

OCTOBER - DECEMBER 15

JULY - SEPTEMBER 15

APRIL - JUNE 15

JANUARY - MARCH 15

OCTOBER - DECEMBER 14

JULY - SEPTEMBER 14

APRIL - JUNE 14

JANUARY - MARCH 14

OCTOBER - DECEMBER 13

JULY - SEPTEMBER 13

APRIL - JUNE 13

JANUARY - MARCH 13

OCTOBER - DECEMBER 12

JULY - SEPTEMBER 12

APRIL - JUNE 12

JANUARY - MARCH 12

OCTOBER - DECEMBER 11

JULY - SEPTEMBER 11

APRIL - JUNE 11

JANUARY - MARCH 11

OCTOBER - DECEMBER 10

JULY - SEPTEMBER 10

APRIL - JUNE 10

JANUARY - MARCH 10

OCTOBER - DECEMBER 09

JULY - SEPTEMBER 09

APRIL - JUNE 09

JANUARY - MARCH 09

OCTOBER - DECEMBER 08

JULY - SEPTEMBER 08

APRIL - JUNE 08

JANUARY - MARCH 08

OCTOBER - DECEMBER 07

JULY - SEPTEMBER 07

APRIL - JUNE 07

JANUARY - MARCH 07

 
  current news   Press   selected story    
     
  9 January 2014  
  Elephant shark genome provides unique insights into gnathostome evolution
 
 



Authors
Byrappa Venkatesh1,2,*, Alison P. Lee1, Vydianathan Ravi1, Ashish K. Maurya31, Michelle M. Lian1, Jeremy B. Swann4, Yuko Ohta5, Martin F. Flajnik5, Yoichi Sutoh6, Masanori Kasahara6, Shawn Hoon7, Vamshidhar Gangu7, Scott W. Roy8, Manuel Irimia9, Vladimir Korzh10, Igor Kondrychyn10, Zhi Wei Lim1, Boon-Hui Tay1, Sumanty Tohari1, Kiat Whye Kong7, Shufen Ho7, Belen Lorente-Galdos11, Javier Quilez11, Tomas Marques-Bonet11, Brian J. Raney12, Philip W. Ingham3, Alice Tay1, LaDeana W. Hillier13, Patrick Minx13, Thomas Boehm4, Richard K. Wilson13, Sydney Brenner1 & Wesley C. Warren13,*

1 - Comparative Genomics Laboratory, Institute of Molecular and Cell Biology, A*STAR, Biopolis,      Singapore.
2 - Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore,      Singapore.
3 - Developmental and Biomedical Genetics Laboratory, Institute of Molecular and Cell Biology, A*STAR,      Biopolis, Singapore.
4 - Department of Developmental Immunology, Max-Planck-Institute of Immunobiology and Epigenetics,      Stuebeweg 51, 79108 Freiburg, Germany.
5 - Department of Microbiology and Immunology, University of Maryland, Baltimore, MD 21201 USA.
6 - Department of Pathology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638,      Japan.
7 - Molecular Engineering Laboratory, Biomedical Sciences Institutes, A*STAR, Biopolis, Singapore.
8 - Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
9 - Banting and Best Department of Medical Research and Donnelly Centre, University of Toronto,      Toronto, M5S 3E1, Canada.
10-Fish Developmental Biology Laboratory, Institute of Molecular and Cell Biology, A*STAR, Biopolis,        Singapore.
11-Institut de Biologia Evolutiva, (UPF-CSIC), PRBB, 08003, Barcelona, Spain.
12-Center for Biomolecular Science and Engineering, School of Engineering, University of California       Santa Cruz, Santa Cruz, CA 95064, USA.
13-The Genome Institute at Washington University, St. Louis, MO, USA.

*Corresponding authors

Published in Nature on 9 January 2014 (Vol 505: 174-179).

To read the Nature article, click here

To see news in Nature, click here

Elephant Shark Genome Project Website: http://esharkgenome.imcb.a-star.edu.sg/

Summary
The emergence of jawed vertebrates (gnathostomes) from jawless vertebrates (agnatha) was accompanied by major morphological and physiological innovations, such as hinged jaws, true teeth, paired fins and immunoglobulin-based adaptive immunity. Gnathostomes subsequently diverged into two groups, the cartilaginous fishes (Chondrichthyes) and the bony vertebrates (Osteichthyes). Here we report the first whole-genome analysis of a cartilaginous fish, the elephant shark (Callorhinchus milii). We find that the C. milii genome is the slowest evolving of all known vertebrates, including the ‘living fossil’ coelacanth, and features extensive synteny conservation with tetrapod genomes, making it a good model for comparative analyses of gnathostome genomes. Our functional studies suggest that the lack of genes encoding secreted calcium-binding phosphoproteins (SCPPs) in cartilaginous fishes explains the absence of bone in their endoskeleton. Furthermore, the adaptive immune system of cartilaginous fishes is unusual: it lacks the canonical CD4 co-receptor and most transcription factors, cytokines and cytokine receptors related to the CD4 lineage, despite the presence of polymorphic major histocompatibility complex class II molecules. It thus presents a new model for understanding the origin of adaptive immunity.

Elephant shark genome is the slowest evolving among known vertebrate genomes. A neutral tree of 13 chordates based on four-fold degenerate (4D) sites shows that the elephant shark possesses the slowest evolving vertebrate genome. The tree is based on 699 protein-coding sequences (strict one-to-one orthologues) from 13 species.

For more information on Byrappa VENKATESH's laboratory, please click here.