SINGAPORE, Jan. 8 (UPI) -- The elephant shark offers clues on factors influencing bone formation and immune system development in cartilaginous fish, Singapore researchers said.
The researchers' sequencing and analysis of the elephant shark genome, the first whole genome of a cartilaginous fish, was reported in Nature this week.
The study of the whole genome in the elephant shark indicates that lack of genes that encode secreted calcium-binding phosphor-proteins may account for the lack of bone in cartilaginous fish, research by Byrappa Venkatesh and colleagues at Sinagpore's Agency for Science, Technology and Research indicated.
Researchers also reported unusual adaptive immunity in elephant sharks, noting that some genes that affect immunity were missing in this fish group. Venkatesh said this finding points up the primitive nature of the adaptive immune system in cartilaginous fishes.