Dolphin genome yields evolutionary insights

June 27, 2012

(Credit: NASA)

The recently sequenced genome of the bottlenose dolphin (Tursiops truncatus) reveals commonalities with other large-brained mammalsNature News Blog reports.

Last fall, researchers at Baylor College of Medicine found 228 gene sequences that had changed significantly relative to other mammals. About 10% of those relate to the nervous system.

One group of genes appears to be important for forming synapses in the brain, while another relates to the bizarre way dolphins sleep with one eye open and half the brain “turned off.” Another set corresponds to genes that in the human brain are related to brain certain disorders, including Alzheimer’s disease and schizophrenia.

One similarity dolphins share with humans and elephants is a decline in the rate of change exhibited by their DNA sequences over time. The team suggests this relates to characteristics such as body size, longevity and generation time — the time between adults and mature offspring — and may  indicate an underlying similar in the evolutionary pressures that shaped the otherwise widely distinct species.